Morass

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Dec 16th, 2020 (edited)
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  1. Good Day to you!
  2.  
  3. I've been asked to make some topic-wise list of problems I've solved. Even though I couldn't involve all problems, I've tried to involve at least "few" problems at each topic I thought up (I'm sorry if I forgot about something "easy"). I've alredy made such list once anyway I've tried to include more problems now — so here it is:
  4.  
  5. <spoiler summary="aho">
  6.  
  7. http://www.spoj.com/problems/ADAJOBS/
  8.  
  9. URI 2226 (5) //[NICE][NUMBERS][DP]
  10.  
  11. http://www.spoj.com/problems/SUB_PROB/en/
  12.  
  13. http://codeforces.com/contest/696/problem/D 8
  14.  
  15. http://www.spoj.com/problems/AHOCUR/ 5 //Aho-Corassic + DP
  16.  
  17. https://www.codechef.com/problems/LYRC (5) //Sample aho-brute-force
  18.  
  19. http://codeforces.com/problemset/problem/346/B //Proposed by [user:bradyawn]
  20.  
  21. </spoiler>
  22.  
  23. <spoiler summary="automat">
  24.  
  25. 6861 [LA] //CYK
  26.  
  27. UVA 10679 //Suffix Automat
  28.  
  29. http://www.spoj.com/problems/STRMATCH/ //Suffix Automat &mdash; trie might do too
  30.  
  31. http://www.spoj.com/problems/NSUBSTR2/ //Suffix Automaton
  32.  
  33. </spoiler>
  34.  
  35. <spoiler summary="belman-ford">
  36.  
  37. UVA 12519
  38.  
  39. http://www.spoj.com/problems/ARBITRAG/ (4) //Or Floyd-Warshall
  40.  
  41. </spoiler>
  42.  
  43. <spoiler summary="bfs">
  44.  
  45. http://www.spoj.com/problems/ADACYCLE/ [FW]
  46.  
  47. UVA 13295 (6) //[NICE][EFFICIENCY][IMPLEMENTATION]
  48.  
  49. http://codeforces.com/gym/101992/problem/H (4) //[VERY NICE][MAX]
  50.  
  51. http://codeforces.com/gym/100112 [H] (3)
  52.  
  53. 6151 - Beehives (4) //[NICE] //Search for shortest cycle
  54.  
  55. https://devskill.com/CodingProblems/ViewProblem/60
  56.  
  57. https://devskill.com/CodingProblems/ViewProblem/150
  58.  
  59. 11312 UVA (3)
  60.  
  61. 11392 UVA (4)
  62.  
  63. http://codeforces.com/contest/653/problem/E (6)
  64.  
  65. http://codeforces.com/contest/769/problem/C 5 //FL:ODD/**** | bfs+greed NICE
  66.  
  67. 10968 UVA (3) //EASY + NICE (bfs withot <=2 nodes)
  68.  
  69. http://codeforces.com/contest/796/problem/D (3) //NICE+EASY ... print visited in bfs (not par)
  70.  
  71. 10888 UVA (4) //VERY NICE &mdash; but not main technique ... ++ DP /or/ MCMF
  72.  
  73. http://codeforces.com/contest/821/problem/D (5) //VERY NICE &mdash; Consider only points not GRID
  74.  
  75. http://www.spoj.com/problems/DIGOKEYS/ (4) //Easy [Nice problem &mdash; weird statement]
  76.  
  77. http://www.spoj.com/problems/SPIKES/ (3) //Easy bfs (# of 's' * 2)
  78.  
  79. http://www.spoj.com/problems/MULTII/ (4) //VERY NICE: BFS over numbers (K*10+d)%N
  80.  
  81. http://www.spoj.com/problems/ADV04F1/ (5) //VERY NICE: [imple] ~ N^4*BigConstant
  82.  
  83. http://www.spoj.com/problems/INVESORT/ (5) //Big limit (really usefull :P)
  84.  
  85. http://codeforces.com/contest/59/problem/E (5) //[NICE][DOUBLE-STATES][SET]
  86.  
  87. http://codeforces.com/contest/877/problem/D (4) //[NICE] Add vector to # of states
  88.  
  89. </spoiler>
  90.  
  91. <spoiler summary="bfs-grid">
  92.  
  93. 4291 - Sculpture (6) //[NICE][PREPROCESS][NORMALIZE]
  94.  
  95. 10977 UVA (3)
  96.  
  97. 928 UVA (3)
  98.  
  99. 13116 UVA (4)
  100.  
  101. 314 UVA (3)
  102.  
  103. 11487 UVA (4)
  104.  
  105. 5622 LA (7)
  106.  
  107. 11931 UVA (5)
  108.  
  109. http://www.spoj.com/problems/KNMOVE/ 3 //simple knights
  110.  
  111. http://www.spoj.com/problems/SERGRID/ 3 //almost classical
  112.  
  113. http://www.spoj.com/problems/NAKANJ/ 3 //Classical chess &mdash; KNIGHT
  114.  
  115. http://www.spoj.com/problems/PUCMM223/ (4) //NICE (but not many languages) &mdash; 2 moving [x][y]
  116.  
  117. http://www.spoj.com/problems/SPIRALGR/ (4) //NICE (not typical) [SIEVE]
  118.  
  119. http://www.spoj.com/problems/DCEPC706/ (4) //NICE &mdash; travelling outside
  120.  
  121. http://codeforces.com/contest/35/problem/C (3) //No obstacles [multiple starts]
  122.  
  123. </spoiler>
  124.  
  125. <spoiler summary="big">
  126.  
  127. https://devskill.com/CodingProblems/ViewProblem/394 (2) //Multiplication (or math)
  128.  
  129. http://codeforces.com/contest/66/problem/A (2) //Big + iffs + implementation
  130.  
  131. UVA &mdash; 10183
  132.  
  133. 10106 &mdash; Product [UVA]
  134.  
  135. 10523 &mdash; Very Easy !!! [UVA]
  136.  
  137. 787 &mdash; Maximum Sub-sequence Product [UVA]
  138.  
  139. 2871 &mdash; Rhyme Schemes [LA][BELL]
  140.  
  141. UVA &mdash; 10497
  142.  
  143. http://www.spoj.com/problems/MUL/en/
  144.  
  145. http://www.spoj.com/problems/ITRIX_E/
  146.  
  147. 11115 &mdash; Uncle Jack
  148.  
  149. 11448 &mdash; Who said crisis? [UVA]
  150.  
  151. http://www.spoj.com/problems/GCD2/
  152.  
  153. 10083 &mdash; Division [UVA]
  154.  
  155. 11830 &mdash; Contract Revision [UVA]
  156.  
  157. 1230 &mdash; MODEX [UVA]
  158.  
  159. http://www.spoj.com/problems/NUMPLAY/
  160.  
  161. 10519 &mdash; UVA
  162.  
  163. 7651 &mdash; Pascal's Hyper-Pyramids [LA]
  164.  
  165. 11344 &mdash; The Huge One [UVA]
  166.  
  167. 10303 &mdash; How Many Trees? [UVA]
  168.  
  169. http://www.spoj.com/problems/FAST2/
  170.  
  171. 495 &mdash; Fibonacci Freeze [UVA]
  172.  
  173. 10023 &mdash; Square root [UVA]
  174.  
  175. http://www.spoj.com/problems/SKYLINE/
  176.  
  177. http://www.spoj.com/problems/NITT2/
  178.  
  179. 11879 &mdash; Multiple of 17
  180.  
  181. http://www.spoj.com/problems/MINNUM/
  182.  
  183. 10494 &mdash; If We Were a Child Again [UVA]
  184.  
  185. 10013 &mdash; Super long sums [UVA]
  186.  
  187. 10925 &mdash; Krakovia [UVA]
  188.  
  189. 10814 &mdash; Simplifying Fractions [UVA]
  190.  
  191. 619 &mdash; Numerically Speaking [UVA]
  192.  
  193. 713 &mdash; Adding Reversed Numbers [UVA]
  194.  
  195. 1226 &mdash; Numerical surprises [UVA]
  196.  
  197. 623 &mdash; 500! [UVA]
  198.  
  199. http://codeforces.com/problemset/problem/18/D
  200.  
  201. http://www.spoj.com/problems/NUMTSN/
  202.  
  203. https://www.codechef.com/problems/FRJUMP
  204.  
  205. 10220 &mdash; I Love Big Numbers ! [UVA]
  206.  
  207. https://www.hackerrank.com/contests/projecteuler/challenges/euler025
  208.  
  209. https://www.hackerrank.com/contests/projecteuler/challenges/euler020
  210.  
  211. 11645 UVA 4
  212.  
  213. Gym &mdash; 100866A [ACM ICPC 2005–2006 NEERC Moscow Subregional Contest]
  214.  
  215. CSQUARE [SPOJ]
  216.  
  217. http://www.spoj.com/problems/PARCARD1/
  218.  
  219. 10070 &mdash; Leap Year or Not Leap Year and .. [UVA]
  220.  
  221. http://www.spoj.com/problems/SOLDIERS/
  222.  
  223. 12333 &mdash; Revenge of Fibonacci [UVA]
  224.  
  225. http://www.spoj.com/problems/NDIVPHI/
  226.  
  227. http://www.spoj.com/problems/IWGBS/ [UVA]
  228.  
  229. http://www.spoj.com/problems/POP3/ [Prime-Test]
  230.  
  231. http://www.spoj.com/problems/VGCD/
  232.  
  233. http://www.spoj.com/problems/NDIVPHI2/
  234.  
  235. 12924 &mdash; Immortal Rabbits [UVA]
  236.  
  237. Count the Trees [UVA][10007]
  238.  
  239. 10198 &mdash; Counting [UVA]
  240.  
  241. 11375 UVA 3
  242.  
  243. http://www.spoj.com/problems/MINNUM/ 3 // BIG/9+!!(BIG%9)
  244.  
  245. 10844 UVA 4 //Bell numbers + big (might be slightly slow!)
  246.  
  247. http://www.spoj.com/problems/NITT2/ 2 //Divisibility by two constants
  248.  
  249. http://www.spoj.com/problems/NUMPLAY/ (3) //With DP
  250.  
  251. http://www.spoj.com/problems/IWGBS/ (3) //Fibonacci 10^4
  252.  
  253. http://www.spoj.com/problems/PUCMM025/ (2) //Divisibility by 1 → 9
  254.  
  255. http://www.spoj.com/problems/CSQUARE/ (3) //Converse + Power
  256.  
  257. http://codeforces.com/contest/17/problem/D (5) //B^(N-1)*(B-1)%C [B/N are big]
  258.  
  259. </spoiler>
  260.  
  261. <spoiler summary="binary_search">
  262.  
  263. https://codeforces.com/contest/1169/problem/C (3) //[NICE]
  264.  
  265. https://codeforces.com/contest/1173/problem/C (4) //[NICE]
  266.  
  267. https://codeforces.com/contest/1201/problem/C (4) //[NICE][SIMPLE]
  268.  
  269. https://codeforces.com/contest/1183/problem/C (3) //[SIMPLE][NICE]
  270.  
  271. http://codeforces.com/gym/101628/problem/J (4) //[NICE][EASY]
  272.  
  273. http://codeforces.com/gym/101962 [F] (5) //[NICE][FW]
  274.  
  275. http://codeforces.com/contest/920/problem/G (5) //[NICE][MATH][IE]
  276.  
  277. http://codeforces.com/contest/140/problem/C (4) //[NICE][GREEDY]
  278.  
  279. http://codeforces.com/contest/898/problem/E (4) //[NICE][SIMPLE][PREPROCESS]
  280.  
  281. http://codeforces.com/contest/888/problem/C (3) //Can be done without BS
  282.  
  283. http://codeforces.com/contest/68/problem/B (3) //[EASY][DOUBLE]
  284.  
  285. http://codeforces.com/contest/42/problem/A (2) //Or simple math
  286.  
  287. http://codeforces.com/contest/883/problem/I (4) //[NICE][SET][2Pointers]
  288.  
  289. http://codeforces.com/contest/51/problem/C (4) //[NICE][GREEDY-CHECK]
  290.  
  291. http://codeforces.com/contest/729/problem/C 3
  292.  
  293. http://codeforces.com/contest/714/problem/D 8
  294.  
  295. 13150 (UVA) 4
  296.  
  297. http://codeforces.com/contest/749/problem/D 5
  298.  
  299. 11692 (UVA) 4
  300.  
  301. 11516 (UVA) 3
  302.  
  303. http://codeforces.com/contest/760/problem/B 3
  304.  
  305. http://codeforces.com/contest/675/problem/D 4 //dunno &mdash; solvable with treap
  306.  
  307. http://www.spoj.com/problems/NDS/ 4 //BS over LIS
  308.  
  309. http://www.spoj.com/problems/VECTAR4/ 3
  310.  
  311. http://codeforces.com/contest/767/problem/D 4 //NICE
  312.  
  313. http://codeforces.com/contest/627/problem/D (7) //with dp &mdash; NICE
  314.  
  315. http://codeforces.com/contest/779/problem/D (3) //NICE + EASY
  316.  
  317. http://www.spoj.com/problems/CNTINDX/ (4) //Map+BS === OK
  318.  
  319. 13177 UVA (3) //BS over answer == OK
  320.  
  321. http://codeforces.com/contest/801/problem/C (3) //BS + SUM -EASY
  322.  
  323. http://codeforces.com/contest/803/problem/D (3) //BS by answer
  324.  
  325. http://codeforces.com/contest/807/problem/C (3) //Or math
  326.  
  327. http://codeforces.com/contest/818/problem/F (4) //NICE &mdash; Live VS Clique
  328.  
  329. http://codeforces.com/contest/845/problem/E (5) //VERY NICE &mdash; min(X,Y) .. add time, repeat
  330.  
  331. http://www.spoj.com/problems/MATHLOVE/ (2) //BS + Gaus (or otter ways)
  332.  
  333. http://www.spoj.com/problems/SABBIRGAME/ (3) //Binary search over answer ::max(0,ANS)
  334.  
  335. http://codeforces.com/contest/846/problem/D (4) //BS+Precalculation OR 2D-RMQ
  336.  
  337. http://www.spoj.com/problems/RPLC/ (3) //Classical
  338.  
  339. http://www.spoj.com/problems/TRIGALGE/ (2) //On doubles &mdash; simple function given
  340.  
  341. http://www.spoj.com/problems/ABA12E/ (4) //VERY NICE &mdash; BS on answer + 2Pointers
  342.  
  343. http://codeforces.com/contest/847/problem/E (4) //NICE: Back+Front OR Front+Back
  344.  
  345. http://www.spoj.com/problems/MAIN8_C/ (3) //Classical &mdash; simultion over array
  346.  
  347. http://www.spoj.com/problems/FUNFACT/ (4) //VERY NICE &mdash; Sterling Approximation
  348.  
  349. http://codeforces.com/contest/16/problem/C (3) //[or math][simple formula check]
  350.  
  351. http://codeforces.com/contest/21/problem/C (3) //[NICE][prefix-sum+lower_bound]
  352.  
  353. http://codeforces.com/contest/24/problem/E (5) //[doubles]
  354.  
  355. http://codeforces.com/contest/875/problem/E (6) //VERY NICE [BS][Keep possible places]
  356.  
  357. </spoiler>
  358.  
  359. <spoiler summary="bits">
  360.  
  361. https://codeforces.com/contest/1204/problem/A (2) //[POWERS]
  362.  
  363. https://codeforces.com/contest/1148/problem/F (6) //[VERY NICE][INDUCTION][CONSTRUCTIVE]
  364.  
  365. https://devskill.com/CodingProblems/ViewProblem/566 (2)
  366.  
  367. https://codeforces.com/gym/102006/problem/F (6) //[VERY NICE][DP]
  368.  
  369. http://codeforces.com/gym/101908/problem/I (3) //[EASY][XOR]
  370.  
  371. http://codeforces.com/contest/879/problem/C (3) //[NICE] one of each operation is enough
  372.  
  373. http://codeforces.com/contest/92/problem/B (2) //Bit addition/shifting (but big number)
  374.  
  375. http://codeforces.com/contest/907/problem/C (3) //Nice but ugly statement: sets
  376.  
  377. 11659 UVA (4)
  378.  
  379. 11535 UVA (4)
  380.  
  381. http://codeforces.com/contest/779/problem/E (5) //NICE + Parsing
  382.  
  383. http://www.spoj.com/problems/EC_CONB/ (1) //reverse numbers
  384.  
  385. http://codeforces.com/contest/769/problem/D (4) //freq + brute-force
  386.  
  387. http://www.spoj.com/problems/HAP01/ (2) //builtin_popcount
  388.  
  389. http://codeforces.com/contest/862/problem/C (3) //VERY NICE &mdash; Random works well
  390.  
  391. http://www.spoj.com/problems/KOMPICI/ (4) //NICE &mdash; Bitmask over digits
  392.  
  393. </spoiler>
  394.  
  395. <spoiler summary="bitset">
  396.  
  397. http://www.spoj.com/problems/ADACOINS/
  398.  
  399. http://www.spoj.com/problems/ADACHERY/
  400.  
  401. http://www.spoj.com/problems/ADAFUROW/
  402.  
  403. https://codeforces.com/contest/1194/problem/E (5) //[NICE][BRUTE]
  404.  
  405. https://www.spoj.com/problems/TTRGRAPH/ (4) //[NICE][GRAPH][CLIQUES]
  406.  
  407. https://www.spoj.com/problems/ILD18ACP/ (5) //[NICE][GRAPH][PATH]
  408.  
  409. http://codeforces.com/contest/914/problem/F (7) //[VERY NICE][POLYMUL-LIKE][BRUTE]
  410.  
  411. http://codeforces.com/contest/117/problem/C (5) //Finding 3cycles in directed graph [NICE]
  412.  
  413. http://codeforces.com/contest/754/problem/E 6
  414.  
  415. http://www.spoj.com/problems/UCBINTC/ 5 //polymul with bitset
  416.  
  417. http://codeforces.com/contest/33/problem/D (4) //VERY NICE [LCA works too]
  418.  
  419. http://codeforces.com/contest/918/problem/C (4) //Brute-force+Bitset (or...)
  420.  
  421. </spoiler>
  422.  
  423. <spoiler summary="bridges">
  424.  
  425. http://codeforces.com/contest/118/problem/E (4) //[NICE]//Orientation [+DFS]
  426.  
  427. 315 &mdash; Network
  428.  
  429. 796 &mdash; Critical Links
  430.  
  431. UVA 12363
  432.  
  433. Gym 100114J [2012-2013 ACM-ICPC, NEERC, Central Subregional Contest]
  434.  
  435. http://www.spoj.com/problems/ONBRIDGE/ [ONLINE][HARD][NICE][D&C]
  436.  
  437. http://codeforces.com/contest/732/problem/F 7
  438.  
  439. http://codeforces.com/contest/700/problem/C 7
  440.  
  441. http://www.spoj.com/problems/EC_P/ (3) //bridges ONLY
  442.  
  443. http://www.spoj.com/problems/SUBMERGE/ (3) //Direct articulation
  444.  
  445. http://www.spoj.com/problems/GRAFFDEF/ (5) //Bridge tree
  446.  
  447. http://codeforces.com/contest/1000/problem/E // Sugested by [user:Muhanad_Alwarareh]
  448.  
  449.  
  450. </spoiler>
  451.  
  452. <spoiler summary="brute-force">
  453.  
  454. https://codeforces.com/gym/102302/problem/A (4) //[RMQ][BS][NEXT]
  455.  
  456. https://codeforces.com/contest/1166/problem/D (4) //[NICE][OBSERVATION][SEQUENCE][COMPLEXITY]
  457.  
  458. https://codeforces.com/contest/1169/problem/D (4) //[NICE][PROOF]
  459.  
  460. https://codeforces.com/contest/1169/problem/B (3) //[VERY NICE][FREQUENCY]
  461.  
  462. https://www.spoj.com/problems/YOSEQ/ (3) //[NICE][OBSERVATION]
  463.  
  464. UVA 13296 (5) //[NICE][RECURSION]
  465.  
  466. http://codeforces.com/gym/100112 (7) [L] //[PRECISION]
  467.  
  468. http://codeforces.com/gym/101806/problem/X (6) //[VERY NICE][DFS][IFS][OBSERVATION]
  469.  
  470. 8259 - High Score [LA] (4) //[VERY NICE][TS works too] add only low number to minimum (NOT WORKING?)
  471.  
  472. http://codeforces.com/contest/922/problem/B (2) //Test all pairs - observe 3rd
  473.  
  474. http://codeforces.com/contest/919/problem/B (1) //Simply simulate
  475.  
  476. http://codeforces.com/contest/146/problem/B (2) //Test all bigger numbers
  477.  
  478. http://codeforces.com/contest/911/problem/B (1)
  479.  
  480. 7692 - Square Deal (4) //Permutations+Swap
  481.  
  482. http://codeforces.com/contest/907/problem/A (2) //try all triples 0→ 200
  483.  
  484. http://codeforces.com/contest/124/problem/B (3) //next-permutation
  485.  
  486. http://codeforces.com/contest/910/problem/C (3) //Next-permutation
  487.  
  488. http://codeforces.com/contest/898/problem/B (2) //Try all possibilities
  489.  
  490. 6160 - Countdown (5) //[NICE][DFS][EFFICIENT?]
  491.  
  492. http://codeforces.com/contest/122/problem/C (3) //Just around 2^10 lucky [RECURSION]
  493.  
  494. 7899 - Mr. Panda and Strips (4) //Weak test-cases
  495.  
  496. 7671 What a Beautiful Lake (2) //Try up/down from every node
  497.  
  498. http://codeforces.com/contest/110/problem/A (1) //4 or 7
  499.  
  500. http://codeforces.com/contest/106/problem/B (2) //Cycles -_-
  501.  
  502. http://codeforces.com/contest/895/problem/A (2) //All segments [in circle]
  503.  
  504. http://codeforces.com/contest/893/problem/B (2) //Try each divisor
  505.  
  506. http://codeforces.com/contest/894/problem/A (1) //3-cycles
  507.  
  508. http://codeforces.com/contest/892/problem/C (3) //Try to find "1" ASAP
  509.  
  510. http://codeforces.com/contest/102/problem/A (2) //Iterate over all triples
  511.  
  512. http://codeforces.com/contest/96/problem/B (2) //Check all
  513.  
  514. http://codeforces.com/contest/94/problem/B (1) //3cycles
  515.  
  516. http://codeforces.com/contest/887/problem/B (3) //Test all numbers
  517.  
  518. http://codeforces.com/gym/101597/problem/A (4) //[MATH][MODULO][SIMULATION]
  519.  
  520. http://codeforces.com/contest/68/problem/C (5) //[VERY NICE][RECURSION][MAX COST MIN FLOW]
  521.  
  522. http://codeforces.com/contest/68/problem/A (1) //Simple simulation
  523.  
  524. http://codeforces.com/contest/66/problem/B (2) //Test always whole platform
  525.  
  526. http://codeforces.com/contest/879/problem/C (3) //[NICE] one of each operation is enough
  527.  
  528. http://codeforces.com/contest/46/problem/C (2) //[2pointers][N^2 works too]
  529.  
  530. http://codeforces.com/contest/47/problem/D (4) //[Implementation][DFS]
  531.  
  532. http://codeforces.com/contest/51/problem/D (4) //Check all/check without 1s/2nd
  533.  
  534. http://code-festival-2017-qualc.contest.atcoder.jp/tasks/code_festival_2017_qualc_b (2)
  535.  
  536. http://codeforces.com/contest/53/problem/B (3) //at most 60 possibilities
  537.  
  538. http://codeforces.com/contest/55/problem/B (3) //Try all permutations & possibilities [NICE]
  539.  
  540. http://codeforces.com/contest/877/problem/B (3) //NICE [N^2][PrefixSum]
  541.  
  542. LA 6623 - Battle for Silver (3) //4 for-cycles inside ~ K4 search
  543.  
  544. UVA 12169 (2)
  545.  
  546. http://codeforces.com/contest/725/problem/C 4
  547.  
  548. http://codeforces.com/contest/725/problem/E 6
  549.  
  550. http://codeforces.com/contest/724/problem/B 3
  551.  
  552. 11961 UVA (2)
  553.  
  554. 11898 UVA (4)
  555.  
  556. 11659 UVA (4)
  557.  
  558. http://codeforces.com/contest/753/problem/C 7
  559.  
  560. 11699 UVA (4)
  561.  
  562. 11548 UVA (3)
  563.  
  564. 11471 UVA (5) //With dynamic programming
  565.  
  566. http://codeforces.com/contest/698/problem/D 8 //with geometry
  567.  
  568. http://codeforces.com/gym/101840 [F] (5) //[NICE][BS][DISTANCE]
  569.  
  570. 11206 UVA (6) //4^20 (but somehow passes)
  571.  
  572. 11214 UVA (6) //Úvaha + pruning
  573.  
  574. 11127 UVA (4) //Simple dfs [just realize you can do so]
  575.  
  576. http://www.spoj.com/problems/BOKAM143SOU/ (3) //just implement for-cycles
  577.  
  578. http://www.spoj.com/problems/BLOPER/ (4) dfs with little pruning
  579.  
  580. 13173 UVA (3) //just brute-force + branching
  581.  
  582. http://codeforces.com/contest/799/problem/D (4) //VERY NICE [only top 34 needed] &mdash; trick with 2 [~20]
  583.  
  584. 10890 UVA (4) //Simple brute-force times out, but with simple pruning AC (answer detection
  585.  
  586. http://codeforces.com/contest/813/problem/B (3) //All*All (BF) care for overflow! NICE & EASY
  587.  
  588. http://codeforces.com/contest/817/problem/C (3) //Check S+Constant (NICE!)
  589.  
  590. 10732 UVA (2) //Brute-force passes .. just don't trust them O(N^2)
  591.  
  592. 10748 UVA (5) //VERY Nice (knights have K^2 moves not 8^K)
  593.  
  594. http://codeforces.com/contest/818/problem/D (4) //NICE for each 'A' check all remaining (max SQRT)
  595.  
  596. http://codeforces.com/contest/834/problem/E (5) //NICE &mdash; hard to imple: all 11122...999 OK
  597.  
  598. http://www.spoj.com/problems/JHAGIRLS/ (4) //Efficient &mdash; or store output in array
  599.  
  600. http://codeforces.com/contest/846/problem/B (3) //Brute-force
  601.  
  602. http://www.spoj.com/problems/ALONE/ (4) //Generate everything <10^15 [NICE]
  603.  
  604. http://codeforces.com/contest/861/problem/B (3) //Check all floor-sizes
  605.  
  606. http://www.spoj.com/problems/RRANGE/ (3) //Compare all queries agains all updates + GAUSS
  607.  
  608. http://codeforces.com/contest/598/problem/B (3) //Treap works too ;-)
  609.  
  610. http://www.spoj.com/problems/AMR10I/ (4) //Can be solved with brute-force with dp
  611.  
  612. http://codeforces.com/contest/868/problem/C (4) //Brute-force (fixet at most 6 each bits)
  613.  
  614. http://codeforces.com/contest/868/problem/D (5) //NICE: Maximal K is low (I assumed 15)
  615.  
  616. http://codeforces.com/contest/31/problem/C (2) //LOW-Constaints: N^2
  617.  
  618. http://codeforces.com/contest/32/problem/D (3) //Simply try all possibilities
  619.  
  620. http://codeforces.com/contest/876/problem/C (3) //Try N and ~100 lower
  621.  
  622. http://codeforces.com/contest/44/problem/B (2) //N^2 works fine
  623.  
  624. </spoiler>
  625.  
  626. <spoiler summary="centroid">
  627.  
  628. https://codeforces.com/gym/101991/problem/A (5) //[VERY NICE][FW]
  629.  
  630. http://codeforces.com/gym/101864 [D] (5) //[NICE][SACK][ARPA][HLD]
  631.  
  632. http://codeforces.com/gym/101840 [E] (5) //NICE
  633.  
  634. DCP-176: Motku2 [DevSkills]
  635.  
  636. http://codeforces.com/contest/715/problem/C 9
  637.  
  638. http://codeforces.com/contest/741/problem/D 8
  639.  
  640. 13164 UVA (7)
  641.  
  642. http://codeforces.com/contest/752/problem/F 5
  643.  
  644. http://codeforces.com/contest/766/problem/E 6
  645.  
  646. http://codeforces.com/contest/833/problem/D 7 //Very nice &mdash; hard (thinking + imple) + FW
  647.  
  648. http://www.spoj.com/problems/HOLI/ (4) //VERY NICE: 2*Distances from centroids
  649.  
  650. </spoiler>
  651.  
  652. <spoiler summary="coloring">
  653.  
  654. https://codeforces.com/gym/102006/problem/K (6) //[VERY NICE][THEOREM][OBSERVATION]
  655.  
  656. http://codeforces.com/contest/741/problem/C 6
  657.  
  658. 11331 UVA (4)
  659.  
  660. http://codeforces.com/contest/664/problem/D 4
  661.  
  662. </spoiler>
  663.  
  664. <spoiler summary="combinatorics">
  665.  
  666. http://www.spoj.com/problems/ADATEAMS/
  667.  
  668. http://www.spoj.com/problems/ADASUM/
  669.  
  670. https://codeforces.com/contest/1166/problem/A (2) //[B2]
  671.  
  672. https://codeforces.com/contest/1207/problem/D (4) //[NICE][FACTORIAL][STL]
  673.  
  674. https://codeforces.com/contest/1204/problem/E (6) //[COMBINATION NUMBERS]
  675.  
  676. https://codeforces.com/contest/1173/problem/D (4) //[VERY NICE][DFS][FACTORIAL]
  677.  
  678. https://atcoder.jp/contests/abc136/tasks/abc136_f (5) //[VERY NICE][IE][POWER][FENWICK]
  679.  
  680. https://codeforces.com/contest/1178/problem/C (3) //[NICE][EASY][POWER]
  681.  
  682. https://codeforces.com/gym/101972/problem/J (4) //[NICE][THEOREM][COMB-NUMBERS]
  683.  
  684. https://codeforces.com/gym/101972/problem/I (5) //[NICE][SHORT][COMB-NUMBERS]
  685.  
  686. http://codeforces.com/gym/101628/problem/G (5) //[NICE][COMB-NUMBERS]
  687.  
  688. http://codeforces.com/gym/101864 [E] (3) //Combination number, power
  689.  
  690. http://codeforces.com/gym/101879/problem/E (2) //Power of 2
  691.  
  692. http://codeforces.com/gym/101873 (5) //Necklace (mby burnside)
  693.  
  694. http://codeforces.com/gym/101808/problem/F (3) //[EASY]][FACTORIAL]
  695.  
  696. http://codeforces.com/problemset/problem/364/A (4) //[NICE][STL-or-sorting][IF]
  697.  
  698. http://codeforces.com/contest/145/problem/D (7) //[VERY NICE][SET][OBSERVATION][BS][BIG]
  699.  
  700. http://codeforces.com/contest/909/problem/B (3)
  701.  
  702. http://codeforces.com/contest/131/problem/C (3) //[EASY][BRUTE-FORCE][COMB-NUMBERS]
  703.  
  704. http://codeforces.com/contest/131/problem/B (2) //[EASY]
  705.  
  706. http://codeforces.com/contest/129/problem/E (5) //[NICE][COMB-NUMBERS]//Observe
  707.  
  708. http://codeforces.com/contest/111/problem/D (5) //[COMB-NUMBERS][POWER][VERY NICE][DP]
  709.  
  710. http://codeforces.com/contest/895/problem/D (4) //[COMB-NUMBERS][OPTI]
  711.  
  712. http://codeforces.com/contest/893/problem/E (5) //[COMB-NUMBERS][NUMBER-THEORY]
  713.  
  714. http://codeforces.com/contest/894/problem/B (3) //try without last row
  715.  
  716. http://codeforces.com/contest/890/problem/E (6) //Permutations
  717.  
  718. http://codeforces.com/contest/52/problem/B (4) //[NICE][PREPROCESS][ROTATION]
  719.  
  720. 3917 //Grid tiling [fancy approximation fomula]
  721.  
  722. http://codeforces.com/contest/760/problem/F
  723.  
  724. https://devskill.com/CodingProblems/ViewProblem/61
  725.  
  726. https://devskill.com/CodingProblems/ViewProblem/255
  727.  
  728. UVA 10918
  729.  
  730. UVA 12576
  731.  
  732. UVA 1118 //Parity
  733.  
  734. http://www.spoj.com/problems/HLP_RAMS/ //Comb parity
  735.  
  736. Project Euler #78: Coin partitions //Partition function
  737.  
  738. http://www.spoj.com/problems/MAIN75/ //DP #of trees
  739.  
  740. 12001 UVA (3)
  741.  
  742. 12034 UVA (4)
  743.  
  744. 11719 UVA (5)
  745.  
  746. 11798 UVA (5)
  747.  
  748. 11282 UVA (4) //dearrangement
  749.  
  750. 11174 UVA (4)
  751.  
  752. http://codeforces.com/contest/666/problem/C 7
  753.  
  754. http://www.spoj.com/problems/JOKER1/ 3 prod(Ai-i)
  755.  
  756. http://www.spoj.com/problems/ANTP/ //4
  757.  
  758. http://codeforces.com/contest/645/problem/E (5) //formula: A[i]=Sum(A)+1
  759.  
  760. http://www.spoj.com/problems/SPCE/ (5) // N^{K-2}*Prod(comp_size)
  761.  
  762. http://codeforces.com/contest/785/problem/D (5) // F'(' C"(+)-1","("
  763.  
  764. 13184 UVA (3)
  765.  
  766. http://codeforces.com/contest/816/problem/D (5) // Observation
  767.  
  768. 13214 (4) //OEIS? : C(N+M-2,N-1)
  769.  
  770. http://codeforces.com/contest/844/problem/B (2) //Easy &mdash; pro prvaky
  771.  
  772. http://www.spoj.com/problems/JOSWAP/ (3) //Frequence array
  773.  
  774. http://www.spoj.com/problems/UCV2013E/ (4) //NICE&EASY: Choose steps to direction
  775.  
  776. http://www.spoj.com/problems/PARCARD1/ (4) //Partition function (raw)
  777.  
  778. http://www.spoj.com/problems/GOODB/ (2) //Easy (NICE): Choose [order]
  779.  
  780. http://www.spoj.com/problems/LOOPEXP/ (4) //A000254/N!
  781.  
  782. http://www.spoj.com/problems/DTPOLY/ (5) //DP might work too
  783.  
  784. http://www.spoj.com/problems/DTPOLY2/ (7) //Harder version of above (NICE but hell)
  785.  
  786. http://www.spoj.com/problems/HC12/ (3) //NICE &mdash; Sort + C(i,K-1)*A[i]
  787.  
  788. http://www.spoj.com/problems/STONE2/ (4) //NICE &mdash; Mostly DP [INVERSION][FACTORIAL]
  789.  
  790. http://www.spoj.com/problems/MAIN8_D/ (5) //NICE &mdash; Suffixes/Prefixes (same add 2^i)
  791.  
  792. http://www.spoj.com/problems/ITRIX_E/ (4) //VERY NICE &mdash; #Nonattacking 2-queens
  793.  
  794. http://www.spoj.com/problems/MAXSUB/ (3) //NICE &mdash; Subsets made of zeroes
  795.  
  796. http://www.spoj.com/problems/SKYLINE/ (3) //Catalan numbers [weird modulo &mdash; care]
  797.  
  798. http://codeforces.com/contest/26/problem/D (5) //Division of two combintion numbers [NI:/]
  799.  
  800. http://codeforces.com/contest/872/problem/E (6) // Prod:Sum(C(DistLines,CompSize))
  801.  
  802. </spoiler>
  803.  
  804. <spoiler summary="constructive">
  805.  
  806. https://codeforces.com/contest/1208/problem/C (4) //[NICE][SEQUENCE][XOR][D&C]
  807.  
  808. https://codeforces.com/contest/1166/problem/B (3) //[NICE][STRINGS][DIVISORS]
  809.  
  810. https://codeforces.com/contest/1206/problem/F (6) //[NICE][OBSERVATION][DFS][CENTROID]
  811.  
  812. https://codeforces.com/contest/1206/problem/C (3) //[NICE]
  813.  
  814. https://codeforces.com/contest/1148/problem/C (4) //[SORTING][PAPERWORK]
  815.  
  816. https://codeforces.com/contest/1174/problem/D (4) //[OBSERVATION][PREFIX SUM][SIMPLE CODING]
  817.  
  818. https://codeforces.com/contest/1174/problem/C (4) //[VERY NICE][SIEVE]
  819.  
  820. https://codeforces.com/contest/1173/problem/B (3) //[VERY NICE][MATH]
  821.  
  822. https://codeforces.com/contest/1202/problem/D (4) //[NICE][MATH][GREEDY]
  823.  
  824. https://codeforces.com/contest/1199/problem/E (5) //[VERY NICE!][OBSERVATION][DFS]
  825.  
  826. https://codeforces.com/contest/1180/problem/D (5) //[VERY NICE][OVSERVATION]
  827.  
  828. https://codeforces.com/contest/1178/problem/D (4) //[VERY NICE][OBSERVATION][NUMBER THEORY]
  829.  
  830. https://codeforces.com/contest/1187/problem/C (4) //[NICE][IMPLEMENTATION]
  831.  
  832. http://codeforces.com/contest/922/problem/F (6) //[NICE][MATH][GREEDY]
  833.  
  834. http://codeforces.com/contest/916/problem/C (3) //Graph construction
  835.  
  836. http://codeforces.com/contest/148/problem/B (3) //[SIMULATION](math or bs)
  837.  
  838. http://codeforces.com/contest/909/problem/F (6) //[VERY NICE][BITS]
  839.  
  840. http://codeforces.com/contest/141/problem/C (4) //[NICE][BRUTE-FORCE]
  841.  
  842. http://codeforces.com/contest/907/problem/D (5) //[VERY NICE][RANDOM]
  843.  
  844. http://codeforces.com/contest/124/problem/C (3) //[NICE][SIEVE]
  845.  
  846. http://codeforces.com/contest/125/problem/C (4) //[NICE][C(N,2)]
  847.  
  848. http://codeforces.com/contest/902/problem/C (4) //[NICE]//Tree isomorphism
  849.  
  850. http://codeforces.com/contest/112/problem/C (3) //[GREEDY]//Max + 1s
  851.  
  852. http://codeforces.com/contest/110/problem/B (2) //Easy modulo
  853.  
  854. http://codeforces.com/contest/894/problem/C (3) //[VERY NICE] //AiAiGCD
  855.  
  856. http://codeforces.com/contest/97/problem/B (4) //NICE - Walls in middles [D&C]
  857.  
  858. http://codeforces.com/contest/85/problem/A (3) //MODULO / SHIFT
  859.  
  860. http://codeforces.com/contest/81/problem/D (3) //NICE - MAX(N/2) - even/odd
  861.  
  862. http://codeforces.com/contest/63/problem/D (3) //NICE[GO BY LINES][4 WAYS B/D ODD/EVEN]
  863.  
  864. http://codeforces.com/contest/42/problem/C (4) //Constructive works too but random is fine :)
  865.  
  866. http://codeforces.com/contest/43/problem/D (3) //NICE - Easy to see [implementation]
  867.  
  868. http://codeforces.com/contest/53/problem/C (2) //EASY [B/E Alternate]
  869.  
  870. http://codeforces.com/contest/877/problem/C (3) //NICE 3*Alternative
  871.  
  872. http://codeforces.com/contest/802/problem/H (6) //We can do "N+k" by adding a letter p+k*x+u+xx
  873.  
  874. http://codeforces.com/contest/12/problem/E (5) //g[i][j]=1+(i+j)%(N-1) [+/-]
  875.  
  876. http://codeforces.com/contest/22/problem/C (4) //Start and then clique without v (+ random)
  877.  
  878. http://codeforces.com/contest/26/problem/C (5) //make Even*Even: do by 2*2 fields
  879.  
  880. http://codeforces.com/contest/41/problem/E (4) //[NICE][CN/2,N/2]
  881.  
  882. http://codeforces.com/contest/78/problem/B (2) //NICE - last 3 and then rest in modulo
  883.  
  884. http://codeforces.com/contest/109/problem/D (5) //[NICE][BACK-POINTERS][SIMULATION][SORT]
  885.  
  886. </spoiler>
  887.  
  888. <spoiler summary="dfs">
  889.  
  890. http://www.spoj.com/problems/ADASEA/
  891.  
  892. https://codeforces.com/contest/1176/problem/E (4) //[NICE][CONSTRUCTIVE][TREE][TOPO]
  893.  
  894. https://codeforces.com/contest/1186/problem/F (5) //[NICE][GREEDY][CONSTRUCTIVE]
  895.  
  896. https://codeforces.com/contest/1189/problem/D2 (5) //[NICE][CONSTRUCTIVE]
  897.  
  898. https://atcoder.jp/contests/agc035/tasks/agc035_b (4) //[NICE][DIRECTION]
  899.  
  900. https://www.spoj.com/problems/CHUNK2/ (3) //[DFS][PRIMES]
  901.  
  902. https://codeforces.com/gym/101981 [K] (4) //[VERY NICE][IMPLE][TREE][SIMULATION]
  903.  
  904. https://www.urionlinejudge.com.br/judge/en/problems/view/1621 (4) //[TREE][IMPLE]
  905.  
  906. https://www.urionlinejudge.com.br/judge/en/problems/view/1610 (3) //[CYCLE]
  907.  
  908. https://www.urionlinejudge.com.br/judge/en/problems/view/2911 (4) //[NICE][RULES][SIMPLE]
  909.  
  910. https://codeforces.com/gym/102001/problem/K (4) //[VERY NICE]
  911.  
  912. https://codeforces.com/gym/101972/problem/B (6) //[VERY NICE][TREE][STL]
  913.  
  914. https://toph.co/p/incompatible-crops (2)
  915.  
  916. http://codeforces.com/gym/100112 [K] (5) //[NICE][BS][COLORING]
  917.  
  918. http://codeforces.com/gym/101962 [D] (6) //[NICE] //Bitset shall work too
  919.  
  920. 4286 - Equilibrium Mobile [LA] (5) //[VERY NICE][OBSERVATION][TREE][DP]
  921.  
  922. http://codeforces.com/gym/101801 (4) [H] //[TREE][DP] //More dfss
  923.  
  924. https://www.urionlinejudge.com.br/judge/en/problems/view/2732 (3) //Easy flood
  925.  
  926. http://codeforces.com/contest/920/problem/E (5) //[NICE][DFS][SET] //Or clever random
  927.  
  928. http://codeforces.com/contest/915/problem/D (4) //[VERY NICE][CYCLES DETECTION (ORIENTED)]
  929.  
  930. http://www.spoj.com/problems/CTTC/ (3) //[EASY][GRAPH-RECONSTRUCTION]
  931.  
  932. 7951 - Islands (3) //[NICE]Flood-Fill
  933.  
  934. http://codeforces.com/contest/901/problem/D (7) //Observations / Tree reduction
  935.  
  936. http://codeforces.com/contest/902/problem/B (3) //No dfs needed
  937.  
  938. http://codeforces.com/gym/101630 {C}(4) //[NICE][SCC]
  939.  
  940. http://codeforces.com/gym/101620 {J}(4) //DFS + multiples of divisors
  941.  
  942. http://codeforces.com/contest/120/problem/F (3) //Width of tree
  943.  
  944. 7606 - Percolation (3) //Dfs on grid [EASY]
  945.  
  946. http://codeforces.com/contest/116/problem/C (2) //[DEPTH]
  947.  
  948. 8080 - Christmas Tree (3) //[SIMPLE][NICE]
  949.  
  950. 6584 - Escape (8) //[VERY VERY VERY NICE][COMPRESSION][MERGING] //Hard but I recommend this one!!
  951.  
  952. 6590 Digraphs (4) //[VERY NICE][CYCLES][DP][IDEA]
  953.  
  954. http://codeforces.com/contest/893/problem/C (3) //Minimum from each connected component
  955.  
  956. http://codeforces.com/contest/884/problem/C (3) //[EASY][PERMUTATIONS][SORTING]
  957.  
  958. http://codeforces.com/contest/883/problem/G (4) //Greedy picking
  959.  
  960. http://codeforces.com/contest/60/problem/B (3) //3D Flood-Fill [NICE][EASY]
  961.  
  962. http://codeforces.com/contest/60/problem/C (4) //[VERY NICE][BF]//Not many real possibilities
  963.  
  964. https://devskill.com/CodingProblems/ViewProblem/3
  965.  
  966. https://devskill.com/CodingProblems/ViewProblem/17
  967.  
  968. https://devskill.com/CodingProblems/ViewProblem/118 //Kind-of
  969.  
  970. 657 &mdash; The die is cast [UVA]
  971.  
  972. 12186 UVA (3)
  973.  
  974. http://codeforces.com/contest/734/problem/E (5)
  975.  
  976. http://codeforces.com/contest/727/problem/A (3)
  977.  
  978. http://codeforces.com/contest/723/problem/E (6)
  979.  
  980. http://codeforces.com/contest/709/problem/E (6)
  981.  
  982. http://codeforces.com/contest/710/problem/E (4)
  983.  
  984. http://codeforces.com/contest/758/problem/E (8)
  985.  
  986. 11323 UVA (5)
  987.  
  988. http://codeforces.com/contest/760/problem/B (3)
  989.  
  990. http://codeforces.com/contest/761/problem/E (6)
  991.  
  992. http://codeforces.com/contest/638/problem/B (3) //connect cons. letters
  993.  
  994. http://codeforces.com/contest/638/problem/C (4) //greedy idea &mdash; easy
  995.  
  996. http://codeforces.com/contest/638/problem/D (5) //spec-DAG articulatin
  997.  
  998. http://codeforces.com/contest/767/problem/C (4)
  999.  
  1000. http://codeforces.com/contest/781/problem/C (5)
  1001.  
  1002. http://codeforces.com/contest/794/problem/D (5) //NICE! Right done dfs
  1003.  
  1004. http://codeforces.com/contest/802/problem/K (5) //Slightly DP-like (NICE) TREE
  1005.  
  1006. http://codeforces.com/contest/813/problem/C (3) //Simply 2 DFS: NICE + EASY
  1007.  
  1008. http://codeforces.com/contest/841/problem/D (4) //DFS while tracking "next"
  1009.  
  1010. http://codeforces.com/contest/845/problem/G (5) //Keep track of cycles
  1011.  
  1012. http://codeforces.com/contest/844/problem/E (5) //Post-Order → line, Connect i → N-2: star
  1013.  
  1014. http://www.spoj.com/problems/CAC/ (5) //VERY NICE! &mdash; Find all cycles in cactus
  1015.  
  1016. http://codeforces.com/contest/849/problem/C (3) //State search by gauss
  1017.  
  1018. http://codeforces.com/contest/846/problem/E (5) //NICE: DFS + some overflow logic
  1019.  
  1020. http://www.spoj.com/problems/KOZE/ (3) //NICE: Floods
  1021.  
  1022. http://www.spoj.com/problems/RIOI_2_3/ (4) //DFS /OR/ BFS /OR/ DSU [NICE][EASY][BF]
  1023.  
  1024. http://www.spoj.com/problems/MAKEMAZE/ (3) //EASY &mdash; Simple dfs on grid
  1025.  
  1026. http://codeforces.com/contest/861/problem/F (5) //VERY NICE: Modify dfs tree so it remains connected
  1027.  
  1028. http://www.spoj.com/problems/GHOSTS/ (3) //NICE &mdash; must remain dag after each QR
  1029.  
  1030. http://www.spoj.com/problems/AMR10J/ (5) //VERY NICE! &mdash; DFS+DP [DAG with cycles]
  1031.  
  1032. http://codeforces.com/contest/24/problem/A (2)//NICE [DFS-ON-CYCLE]
  1033.  
  1034. http://codeforces.com/contest/29/problem/C (3) //Find begining/end of line (graph)
  1035.  
  1036. http://codeforces.com/contest/29/problem/D (4) //Tree [implementation][simulation]
  1037.  
  1038. </spoiler>
  1039.  
  1040. <spoiler summary="digits">
  1041.  
  1042. https://devskill.com/CodingProblems/ViewProblem/564 (2) //[OBSERVATION]
  1043.  
  1044. http://www.spoj.com/problems/PR003004/ (4) //Simple digits count
  1045.  
  1046. http://codeforces.com/contest/770/problem/B (3) //max num max digsum
  1047.  
  1048. </spoiler>
  1049.  
  1050. <spoiler summary="dijkstra">
  1051.  
  1052. http://www.spoj.com/problems/ADATRIP/
  1053.  
  1054. https://www.urionlinejudge.com.br/judge/en/problems/view/1655 (4) //[EASY][PROBABILITY]
  1055.  
  1056. https://www.urionlinejudge.com.br/judge/en/problems/view/2910 (4) //[TREE]
  1057.  
  1058. http://codeforces.com/gym/101628/problem/f (4)
  1059.  
  1060. http://codeforces.com/gym/100112 [E] (6) //[NICE][BS][GEOMETRY]
  1061.  
  1062. http://codeforces.com/gym/101845/problem/J (5) //[NICE][OBSERVATION][TWICE]
  1063.  
  1064. http://codeforces.com/gym/101801 [K] (5) //[NICE][MULTIPLE NODES]
  1065.  
  1066. http://codeforces.com/gym/101879/problem/F (8) //[NICE][BRIDGE]
  1067.  
  1068. http://codeforces.com/gym/101666 [D] (4) //[NICE]
  1069.  
  1070. http://codeforces.com/contest/144/problem/D (4) //[VERY NICE][IFS]
  1071.  
  1072. http://www.spoj.com/problems/ADRABR/ (3) //Classical dijkstra - bad statement
  1073.  
  1074. http://codeforces.com/contest/141/problem/D (5) //[NICE]Many Conditions
  1075.  
  1076. 6583 Subway (5) //[NICE]//Not exactly dijkstra by slightly similar [IMPLEMENTATION]
  1077.  
  1078. 3850 [LA]
  1079.  
  1080. Gym 100625D [2013 Benelux Algorithm Programming Contest (BAPC 13)]
  1081.  
  1082. UVA 12950
  1083.  
  1084. Gym 100753A [2015 German Collegiate Programming Contest (GCPC 15) + POI 10-T3]
  1085.  
  1086. UVA 13030
  1087.  
  1088. UVA 1027
  1089.  
  1090. UVA 11377
  1091.  
  1092. http://codeforces.com/problemset/problem/843/D
  1093.  
  1094. 11813 UVA
  1095.  
  1096. Gym 101242B [2016 ACM-ICPC World Finals] //+DP
  1097.  
  1098. Gym 100923B [2015 ACM National Contest Romania &mdash; Round 1]
  1099.  
  1100. UVA 11833
  1101.  
  1102. http://www.spoj.com/problems/EZDIJKST/en/
  1103.  
  1104. LightOJ 1019
  1105.  
  1106. UVA 13010 //+TS
  1107.  
  1108. 2819 [LA]
  1109.  
  1110. UVA 12144
  1111.  
  1112. http://codeforces.com/contest/716/problem/D 7
  1113.  
  1114. 12047 UVA 4
  1115.  
  1116. 11514 UVA 4
  1117.  
  1118. http://codeforces.com/contest/757/problem/F 7
  1119.  
  1120. 11338 UVA (4)
  1121.  
  1122. 11374 UVA (4)
  1123.  
  1124. 11097 UVA (4) //Divide to N*1000 nodes and go!
  1125.  
  1126. 13172 UVA (5) //6*DJ per query + permutations
  1127.  
  1128. 10816 UVA (4) //Easy Linear-Search by answer + DJ with path
  1129.  
  1130. http://codeforces.com/contest/827/problem/F 7 //Very nice &mdash; Even&Odd
  1131.  
  1132. http://www.spoj.com/problems/DELIVER/ (5) //Normalize coordinates + Optimalize
  1133.  
  1134. http://www.spoj.com/problems/CCHESS/ (4) //Dijkstra as knight
  1135.  
  1136. </spoiler>
  1137.  
  1138. <spoiler summary="divide_conquer">
  1139.  
  1140. https://codeforces.com/contest/1175/problem/F (7) //[VERY NICE][HASH][RANDOMISATION]
  1141.  
  1142. https://codeforces.com/contest/1181/problem/E2 (7) //[VERY NICE][SORTING][ST]
  1143.  
  1144. https://codeforces.com/contest/1181/problem/E1 (5) //[VERY NICE][OBSERVATION][SORTING]
  1145.  
  1146. https://codeforces.com/gym/102058/problem/G (7) //[VERY NICE][BS][PRIORITY_Q]
  1147.  
  1148. http://codeforces.com/gym/101845/problem/L (6) //[VERY NICE][INDUCTION]
  1149.  
  1150. http://codeforces.com/gym/101801 [J] (5) //[NICE][TRIE][RMQ]
  1151.  
  1152. 8257 - Factor-Free Tree [LA] (6) //[VERY VERY NICE][PRIMES][FACTOR]
  1153.  
  1154. https://www.urionlinejudge.com.br/judge/en/problems/view/1683 (4) //RAW histogram
  1155.  
  1156. http://codeforces.com/contest/817/problem/D (5) //Very nice NlogN
  1157.  
  1158. http://www.spoj.com/problems/DYNACON2/ (8) //Lesser hell &mdash; offline Nlog(N) /or/ NlogN^2
  1159.  
  1160. http://codeforces.com/contest/876/problem/F (5) //VERY NICE &mdash; Find greatest + next/back functions
  1161.  
  1162. </spoiler>
  1163.  
  1164. <spoiler summary="divisors">
  1165.  
  1166. https://codeforces.com/gym/102302/problem/B (4) //[FACTORISATION][NUMBER THEORY]
  1167.  
  1168. https://codeforces.com/contest/1176/problem/D (4) //[NICE][GREEDY][SORTING]
  1169.  
  1170. https://atcoder.jp/contests/abc136/tasks/abc136_e (5) //[NICE][GREEDY][DIVISORS]
  1171.  
  1172. https://codeforces.com/contest/1183/problem/F (5) //[VERY NICE][SORTING][OBSERVATION][BF]
  1173.  
  1174. https://www.spoj.com/problems/KPOWERSUM/ (4) //[FACTORISATION]
  1175.  
  1176. http://codeforces.com/gym/101992/problem/D (5) //[VERY NICE][IE][NUMBER THEORY]
  1177.  
  1178. http://codeforces.com/gym/101982 [B] (5) //[FACTORISATION][GCD][SIEVE]
  1179.  
  1180. http://codeforces.com/gym/101864 [G] (5) //[VERY NICE][FACTORISATION][GCD]
  1181.  
  1182. http://codeforces.com/gym/101840 [D] (4) //[EVENTS][NICE]
  1183.  
  1184. http://codeforces.com/gym/101741/problem/F (6) //[NICE][PROBABILITY][GCD]
  1185.  
  1186. http://www.spoj.com/problems/FRNDAM/ (3) //Simply find sum of all divisors (low constraints)
  1187.  
  1188. http://codeforces.com/contest/920/problem/F (5) //[NICE][FAST FALL][SET][DIVISORS]
  1189.  
  1190. 7726 A Simple Math Problem (4) //TLE if naive (consider only divisors)
  1191.  
  1192. http://codeforces.com/contest/112/problem/D (4) //[NICE] Last-position [FACTOR]
  1193.  
  1194. http://codeforces.com/contest/75/problem/C (3) //[NICE][BS]
  1195.  
  1196. LightOJ 1068
  1197.  
  1198. LightOJ 1134
  1199.  
  1200. Project Euler #95: Amicable chains
  1201.  
  1202. NAJ0001 &mdash; Divisible Number Sum [SPOJ]
  1203.  
  1204. http://www.spoj.com/problems/LCMSUM/
  1205.  
  1206. https://www.hackerrank.com/contests/101hack38/challenges/easy-gcd-1/problem
  1207.  
  1208. UVA 13085
  1209.  
  1210. http://www.spoj.com/problems/CDRSANJ/
  1211.  
  1212. http://www.spoj.com/problems/DIVSEQ/
  1213.  
  1214. UVA 12154
  1215.  
  1216. UVA 13058
  1217.  
  1218. http://www.spoj.com/problems/EC_DIVS/
  1219.  
  1220. https://www.codechef.com/problems/CHEFKEY
  1221.  
  1222. http://codeforces.com/problemset/problem/671/C
  1223.  
  1224. Gym 101411G [2009-2010 ACM-ICPC, NEERC, Western Subregional Contest]
  1225.  
  1226. http://codeforces.com/problemset/problem/831/F
  1227.  
  1228. http://codeforces.com/problemset/problem/839/D
  1229.  
  1230. 12934 &mdash; Factorial Division [UVA]
  1231.  
  1232. UVA 10880
  1233.  
  1234. http://www.spoj.com/problems/PSTR/
  1235.  
  1236. http://codeforces.com/problemset/problem/27/E
  1237.  
  1238. [LA] 3014
  1239.  
  1240. UVA 12843
  1241.  
  1242. https://www.urionlinejudge.com.br/judge/en/problems/view/1164
  1243.  
  1244. http://codeforces.com/problemset/problem/803/F
  1245.  
  1246. 10892 &mdash; LCM Cardinality
  1247.  
  1248. http://www.spoj.com/problems/GCDEX/
  1249.  
  1250. http://www.spoj.com/problems/INVDIV/
  1251.  
  1252. 13083 &mdash; Yet another GCDSUM //ll
  1253.  
  1254. http://www.spoj.com/problems/IITKWPCF/ //ll
  1255.  
  1256. UVA 13185
  1257.  
  1258. UVA 13194
  1259.  
  1260. UVA 11388
  1261.  
  1262. http://www.spoj.com/problems/SAS002/
  1263.  
  1264. 12425 &mdash; Best Friend
  1265.  
  1266. http://codeforces.com/problemset/problem/703/E
  1267.  
  1268. https://www.hackerearth.com/problem/algorithm/harry-gets-into-infy/
  1269.  
  1270. UVA 10830 //SUM
  1271.  
  1272. http://www.spoj.com/problems/DIVSUM/en/ //SUM
  1273.  
  1274. http://www.spoj.com/problems/AFS/ //SUM
  1275.  
  1276. UVA 11526 //SUM
  1277.  
  1278. </spoiler>
  1279.  
  1280. <spoiler summary="dp">
  1281.  
  1282. http://www.spoj.com/problems/ADAZOO/
  1283.  
  1284. http://www.spoj.com/problems/ADASEQEN/
  1285.  
  1286. http://www.spoj.com/problems/ADAMOLD/
  1287.  
  1288. http://www.spoj.com/problems/ADASALE/
  1289.  
  1290. https://codeforces.com/gym/102302/problem/E
  1291.  
  1292. https://codeforces.com/gym/102307/problem/G (4) //[DAG][PRIORITY][GREEDY]
  1293.  
  1294. https://codeforces.com/contest/1208/problem/F (6) //[VERY NICE][BITS][GREEDY][SOS]
  1295.  
  1296. https://codeforces.com/contest/1174/problem/E (6) //[VERY NICE][NUMBER THEORY][OBSERVATION]
  1297.  
  1298. https://codeforces.com/contest/1203/problem/F2 (6) //[VERY NICE][GREEDY][SORTING][CASES]
  1299.  
  1300. https://codeforces.com/contest/1176/problem/F (5) //[NICE][IMPLE][SORTING]
  1301.  
  1302. https://codeforces.com/contest/1200/problem/F (6) //[NICE][DFS][GRAPH][LCM][MATH]
  1303.  
  1304. https://codeforces.com/contest/1201/problem/D (5) //[NICE][DP][IMPLE][CASES]
  1305.  
  1306. https://www.spoj.com/problems/THECODE/ (4) //[BITMASK]
  1307.  
  1308. https://codeforces.com/contest/1199/problem/F (5) //[NICE][DIMENSIONS]
  1309.  
  1310. https://codeforces.com/contest/1183/problem/H (4) //[NICE][SUBSEQUENCE][NEXT]
  1311.  
  1312. https://codeforces.com/contest/1183/problem/E (4) //[NICE][SUBSEQUENCE][NEXT]
  1313.  
  1314. https://codeforces.com/contest/1178/problem/F2 (7) //[VERY NICE][OBSERVATION]
  1315.  
  1316. https://codeforces.com/contest/1178/problem/F1 (5) //[NICE][MATH][REDUCTION]
  1317.  
  1318. https://codeforces.com/contest/1178/problem/B (3) //[EASY]Not even real DP
  1319.  
  1320. https://codeforces.com/contest/1195/problem/C (3) //[EASY]
  1321.  
  1322. https://codeforces.com/contest/1189/problem/F (6) //[VERY NICE][OBSERVATION]
  1323.  
  1324. https://atcoder.jp/contests/agc035/tasks/agc035_d (5) //[VERY NICE][BIT][IDEA]
  1325.  
  1326. https://www.spoj.com/problems/PLOVER/ (4) //[NICE][DIGITS]
  1327.  
  1328. https://www.spoj.com/problems/NICESEQ/ (4) //[DIGITS][POSSIBLY FASTER]
  1329.  
  1330. https://codeforces.com/gym/101981 [L] (5) //[NICE]
  1331.  
  1332. https://www.spoj.com/problems/RANDMOD/ (4) //[OBSERVATION][SEQUENCE]
  1333.  
  1334. https://www.urionlinejudge.com.br/judge/en/problems/view/1592 (4) //[GRAPH]
  1335.  
  1336. https://www.urionlinejudge.com.br/judge/en/problems/view/2824 (4) //Classical
  1337.  
  1338. https://codeforces.com/gym/102006/problem/D (4) //[NICE][OBSERVATION]
  1339.  
  1340. https://codeforces.com/gym/102021 [K] (4)
  1341.  
  1342. https://codeforces.com/gym/102058/problem/D (5) //[NICE][DOMINATION]
  1343.  
  1344. UVA 13294 (4) //[BIT]
  1345.  
  1346. http://codeforces.com/gym/101992/problem/A (6) //[BITS][OBSERVATION]
  1347.  
  1348. http://codeforces.com/gym/101628/problem/H (3) //[NICE][CLASSICAL][DAG]
  1349.  
  1350. http://codeforces.com/gym/101628/problem/A (3)
  1351.  
  1352. http://codeforces.com/gym/100112 [J] (4) //[NICE][TREE]
  1353.  
  1354. http://codeforces.com/gym/101982 [D] (5) //[VERY NICE][BITS] //Window
  1355.  
  1356. http://codeforces.com/gym/101982 [C] (4) //Classical combinatorics
  1357.  
  1358. http://codeforces.com/gym/101845/problem/E (5)
  1359.  
  1360. https://www.codechef.com/problems/SPECTAC (5) //[NICE]
  1361.  
  1362. http://codeforces.com/gym/101801 [E]
  1363.  
  1364. http://codeforces.com/gym/101801 [D] (6) //[VERY NICE][SEGMENT TREE][SORTING][NORMALIZE]
  1365.  
  1366. http://codeforces.com/gym/101873 [J] (7) //[NICE][IMPLEMENTATION][STRING][SUBSUBSET]
  1367.  
  1368. http://codeforces.com/gym/101889 [E] (4)
  1369.  
  1370. http://codeforces.com/gym/101808/problem/D (7) //[NICE][OPTIMISATION][EFFICIENCY]
  1371.  
  1372. http://codeforces.com/gym/101666 [I] (4)
  1373.  
  1374. http://codeforces.com/gym/101840 [A] (4) //Doubles
  1375.  
  1376. DevSkills 475: Bunty's Xor Game (4) //[BITS][GAME THEORY]
  1377.  
  1378. https://www.devskill.com/CodingProblems/ViewProblem/489 (5) //[NICE][FACTORISATION]
  1379.  
  1380. DevSkills 534 (4) //[BITSET][COMBINATIONS]
  1381.  
  1382. http://codeforces.com/gym/101650 [D] (5) //Not hard - more coding + printing
  1383.  
  1384. 13286 - Ingredients (4) //[NICE][DAG] Classical
  1385.  
  1386. 8299 - Bricks (5) //[NICE][COMBINATORICS][SORTING]
  1387.  
  1388. http://codeforces.com/contest/934/my (4) //Subsequence
  1389.  
  1390. http://codeforces.com/contest/922/problem/E (5) //find max mana
  1391.  
  1392. http://codeforces.com/contest/920/problem/D (4) //[NICE][KNAPSACK-MODULO][GREEDY]
  1393.  
  1394. http://codeforces.com/contest/919/problem/D (4) //[NICE][DFS][CYCLE][DAG]
  1395.  
  1396. http://codeforces.com/contest/914/problem/C (3) //[DIGITS][BINARY]
  1397.  
  1398. http://codeforces.com/contest/913/problem/E (5) //[NICE][EXPRESSION]
  1399.  
  1400. http://codeforces.com/contest/148/problem/E (5) //[DP][PREFIX SUM][GREED]
  1401.  
  1402. http://www.spoj.com/problems/PALMKR/ (4) //Classical palindrome + print + lexicography
  1403.  
  1404. http://codeforces.com/contest/146/problem/E (5) //[NICE][COMBINATORICS][OBSERVATION]
  1405.  
  1406. http://codeforces.com/contest/909/problem/C (4) //[NICE][CLASSICAL][EASY]
  1407.  
  1408. 7785 - m-ary Partitions (4) //Combinatorics
  1409.  
  1410. http://codeforces.com/contest/133/problem/E (4) //[IMPLEMENTATION]
  1411.  
  1412. http://codeforces.com/contest/126/problem/D (5) //[NICE]//Decomposet DP//Own hash-map
  1413.  
  1414. http://codeforces.com/contest/910/problem/B (3) //Or many other ways
  1415.  
  1416. 6154 RNA Secondary Structure (5) //[NICE] Unoptimal might work too
  1417.  
  1418. https://arc087.contest.atcoder.jp/tasks/arc087_b (4) //[VERY NICE][OBSERVATION]
  1419.  
  1420. http://codeforces.com/contest/903/problem/F (5) //[VERY NICE][BITMASK][BRUTE]
  1421.  
  1422. http://codeforces.com/contest/903/problem/A (2) //Easy knapsack-like // Low constraints
  1423.  
  1424. http://codeforces.com/contest/900/problem/E (4) //[NICE]//Patter-match: FFT or KMP or Brute-Force
  1425.  
  1426. http://codeforces.com/contest/118/problem/D (3) //[COMBINATORICS][LOW-CONSTRAINTS]
  1427.  
  1428. http://codeforces.com/contest/115/problem/E (5) //[VERY NICE][SEGMENT TREE]
  1429.  
  1430. http://codeforces.com/contest/116/problem/D (3) //CLASSICAL[LOW-CONSTRAINTS]
  1431.  
  1432. 10128 Queue (uva) (4) //One possibility is bitmask - second combinatorics
  1433.  
  1434. http://codeforces.com/contest/110/problem/C (3) //[EASY]// Greedy/math works too
  1435.  
  1436. 8078 - Bracket Sequence (4) //[VERY NICE][DP-LINKS]
  1437.  
  1438. http://codeforces.com/contest/106/problem/C (3) //[NICE][EASY]
  1439.  
  1440. http://codeforces.com/contest/895/problem/C (4) //[NICE]
  1441.  
  1442. 8024 Stack Construction (4) //[NICE] Palindromic style - but not exactly
  1443.  
  1444. 7708 - Cubes (6) //[MATH]
  1445.  
  1446. http://codeforces.com/contest/888/problem/F (6) //[NICE][FLAG]
  1447.  
  1448. http://www.spoj.com/problems/ACQUIRE/ (5) //[NICE][CH-OPT]
  1449.  
  1450. http://codeforces.com/contest/319/problem/C (6) //[NICE][CH-OPT]
  1451.  
  1452. http://www.spoj.com/problems/NKLEAVES/ (5) //[NICE][DC]
  1453.  
  1454. http://codeforces.com/contest/76/problem/D (4) //[BITS][OVERFLOW]
  1455.  
  1456. http://codeforces.com/contest/73/problem/C (4) //[NICE][EASY][TRY-ALL-LETTERS]
  1457.  
  1458. http://codeforces.com/contest/67/problem/C (4) //[NICE][LEAVENSTEIN]
  1459.  
  1460. http://codeforces.com/contest/67/problem/A (3) //[EASY][PRINTING][OTHER POSSIBLE WAYS]
  1461.  
  1462. http://codeforces.com/contest/55/problem/D (5) //[NICE][DIGITS][EFFICIENT]
  1463.  
  1464. http://codeforces.com/contest/56/problem/D (4) //String modification + printing [NICE]
  1465.  
  1466. http://codeforces.com/contest/58/problem/E (6) //[NICE][IMPLEMENTATION]
  1467.  
  1468. UVA 12181
  1469.  
  1470. https://devskill.com/CodingProblems/ViewProblem/21
  1471.  
  1472. https://devskill.com/CodingProblems/ViewProblem/37
  1473.  
  1474. https://devskill.com/CodingProblems/ViewProblem/71
  1475.  
  1476. https://devskill.com/CodingProblems/ViewProblem/103
  1477.  
  1478. https://devskill.com/CodingProblems/ViewProblem/107
  1479.  
  1480. https://devskill.com/CodingProblems/ViewProblem/115
  1481.  
  1482. https://devskill.com/CodingProblems/ViewProblem/126
  1483.  
  1484. https://devskill.com/CodingProblems/ViewProblem/131
  1485.  
  1486. https://devskill.com/CodingProblems/ViewProblem/134
  1487.  
  1488. https://devskill.com/CodingProblems/ViewProblem/174
  1489.  
  1490. https://devskill.com/CodingProblems/ViewProblem/186
  1491.  
  1492. https://devskill.com/CodingProblems/ViewProblem/201
  1493.  
  1494. https://devskill.com/CodingProblems/ViewProblem/338
  1495.  
  1496. https://devskill.com/CodingProblems/ViewProblem/368
  1497.  
  1498. https://devskill.com/CodingProblems/ViewProblem/392
  1499.  
  1500. https://devskill.com/CodingProblems/ViewProblem/399
  1501.  
  1502. https://www.hackerrank.com/contests/world-codesprint-5/challenges/mining //Opti
  1503.  
  1504. UVA 12915 //Opti
  1505.  
  1506. UVA 12524 //Opti
  1507.  
  1508. http://codeforces.com/problemset/problem/631/E //CH
  1509.  
  1510. https://devskill.com/CodingProblems/ViewProblem/6
  1511.  
  1512. https://devskill.com/CodingProblems/ViewProblem/11
  1513.  
  1514. 11552 UVA (3)
  1515.  
  1516. 12172 UVA (3)
  1517.  
  1518. 4507 LA (5)
  1519.  
  1520. 4510 LA (5) [+ geometry]
  1521.  
  1522. 12181 UVA (6)
  1523.  
  1524. http://codeforces.com/contest/729/problem/F 6
  1525.  
  1526. http://codeforces.com/contest/735/problem/E 9
  1527.  
  1528. http://codeforces.com/contest/731/problem/E 5
  1529.  
  1530. 12030 UVA (4)
  1531.  
  1532. http://codeforces.com/contest/721/problem/E 7
  1533.  
  1534. http://codeforces.com/contest/742/problem/D 4
  1535.  
  1536. 12040 UVA (5)
  1537.  
  1538. http://codeforces.com/contest/712/problem/D 5
  1539.  
  1540. 13162 UVA (6)
  1541.  
  1542. http://codeforces.com/contest/743/problem/E 6
  1543.  
  1544. 11908 UVA (3)
  1545.  
  1546. 11932 UVA (4)
  1547.  
  1548. http://codeforces.com/contest/745/problem/E (7)
  1549.  
  1550. 11806 UVA (4)
  1551.  
  1552. http://codeforces.com/contest/747/problem/F (5)
  1553.  
  1554. 11843 UVA (4)
  1555.  
  1556. http://codeforces.com/contest/752/problem/E (5)
  1557.  
  1558. http://codeforces.com/contest/703/problem/E (7)
  1559.  
  1560. 11753 UVA (4)
  1561.  
  1562. 11725 UVA (5)
  1563.  
  1564. http://codeforces.com/contest/722/problem/E (9)
  1565.  
  1566. http://codeforces.com/contest/760/problem/F (8)
  1567.  
  1568. 11795 UVA (3)
  1569.  
  1570. 11654 UVA (4)
  1571.  
  1572. 11523 UVA (5)
  1573.  
  1574. 11404 UVA (4)
  1575.  
  1576. 11432 UVA (4)
  1577.  
  1578. 11451 UVA (4) //C==20 mistake in statement
  1579.  
  1580. 11301 UVA (4)
  1581.  
  1582. http://codeforces.com/contest/762/problem/D 5
  1583.  
  1584. 11361 UVA (4) //digit DP
  1585.  
  1586. 11365 UVA (7)
  1587.  
  1588. 11391 UVA (4) //easy+implementation
  1589.  
  1590. 11394 UVA (3)
  1591.  
  1592. 11218 UVA (2)
  1593.  
  1594. 11125 UVA (4) //slightly implementation
  1595.  
  1596. 11076 UVA (3)
  1597.  
  1598. 11081 UVA (4) //3 string subsequences (beware of fail)
  1599.  
  1600. http://codeforces.com/contest/678/problem/E (5) //bitset dp + probability
  1601.  
  1602. http://codeforces.com/contest/766/problem/C (4)
  1603.  
  1604. http://codeforces.com/contest/667/problem/C (3)
  1605.  
  1606. http://www.spoj.com/problems/MOVIFAN/ (3)
  1607.  
  1608. http://www.spoj.com/problems/ORDSUM23/ (3)
  1609.  
  1610. http://www.spoj.com/problems/DIVSEQ/ (4) //N^3 (but better...) works fine
  1611.  
  1612. http://codeforces.com/contest/633/problem/F (7) //Tree dp
  1613.  
  1614. http://www.spoj.com/problems/ADJDUCKS/ (4) sort + pick 2-3 continous O(N)
  1615.  
  1616. http://www.spoj.com/problems/JLNT/ (4) //pick 0 or 2 | 1e3*5e3
  1617.  
  1618. http://www.spoj.com/problems/TPCPALIN/ (5) //500^3 works (3rd countable)
  1619.  
  1620. http://www.spoj.com/problems/COLORSEG/ (4) //50^4==OK 50^4log(N)=TLE NICE
  1621.  
  1622. http://www.spoj.com/problems/POWERCAR/ (3) //1e3*1e3*2 &mdash; follow rules
  1623.  
  1624. http://www.spoj.com/problems/INGRED/ (5) //TSP-like [reduce + go]
  1625.  
  1626. http://www.spoj.com/problems/BADXOR/ (4) //classical subsets
  1627.  
  1628. http://www.spoj.com/problems/SPCO/ (5) //64*64*2 DP {OPT: prime O(1) + clear only half}
  1629.  
  1630. http://www.spoj.com/problems/WAYHOME/ (5) //NICE: 1) 1*1 b)12,1,**,2
  1631.  
  1632. http://www.spoj.com/problems/NFURY/ (2) //Minimal sum of squares
  1633.  
  1634. http://www.spoj.com/problems/GDIL/ (3) //combinatorics
  1635.  
  1636. http://codeforces.com/contest/791/problem/D (5) //Tree
  1637.  
  1638. http://codeforces.com/contest/791/problem/E (6) //V,K,X &mdash; pick any
  1639.  
  1640. http://codeforces.com/contest/789/problem/C (3)
  1641.  
  1642. 13176 (4) //N^6
  1643.  
  1644. 13179 (5) //NICE [Ath][Bth][TimeDiff]
  1645.  
  1646. http://codeforces.com/contest/796/problem/E (6) //NICE: N*P*K*K (WC can't happen!)
  1647.  
  1648. http://codeforces.com/contest/797/problem/E (4) //NICE: Almost BF-able (but care of low K)
  1649.  
  1650. http://codeforces.com/contest/793/problem/D (3) //NICE & EASY: begin/end/actual/USED
  1651.  
  1652. http://codeforces.com/contest/803/problem/E (4) //State search &mdash; many IF's (EASY)
  1653.  
  1654. http://codeforces.com/contest/805/problem/F (7) //NICE: DP on tree + fast BF + hack
  1655.  
  1656. http://codeforces.com/contest/808/problem/E (5) //NICE!
  1657.  
  1658. http://codeforces.com/contest/811/problem/C (4) //Precalculate + DP (greedy thinking)
  1659.  
  1660. 10817 UVA 4 //Easy but slightly implementation
  1661.  
  1662. 10859 UVA 4 //Nice &mdash; on tree .. but for a reason small constrains
  1663.  
  1664. 10898 UVA 4 //Hash is lesser than 1e6 .. try everything
  1665.  
  1666. http://codeforces.com/contest/812/problem/B (3) //Not only DP, yet imho easiest ..many spec cases
  1667.  
  1668. http://codeforces.com/contest/813/problem/D (5) //VERY VERY NICE &mdash; N*N (none picked between a/b)
  1669.  
  1670. http://codeforces.com/contest/814/problem/E 5 //VERY NICE &mdash; Harder imple: Combinatorics
  1671.  
  1672. http://codeforces.com/problemset/problem/816/E (6) //NICE &mdash; Tree (hard 2C complexity)
  1673.  
  1674. http://codeforces.com/contest/837/problem/D (5) //NICE &mdash; yet kinda pain [must be iterative]
  1675.  
  1676. http://www.spoj.com/problems/AUT/ (4) //NICE &mdash; K is interesting ~ at most 1600
  1677.  
  1678. http://www.spoj.com/problems/GNYR04C/ (3) //Easy &mdash; Nice idea [Big→ Low approach]
  1679.  
  1680. http://www.spoj.com/problems/TIEROPE/ (4) //Process 2*L ~ otherwise pick BIG
  1681.  
  1682. http://www.spoj.com/problems/IITKWPCE/ (4) //Palindromes [efficiency!] &mdash; NICE!
  1683.  
  1684. IITKWPCD SPOJ (4) //+Slightly geometry
  1685.  
  1686. UVA 1496 //[Steiner's Tree] Very Nice (8)
  1687.  
  1688. http://www.spoj.com/problems/LKS/ (3) //Classical knapsack
  1689.  
  1690. http://www.spoj.com/problems/UOFTAE/ (3) //Easy & Sympatic DP
  1691.  
  1692. http://www.spoj.com/problems/DCOWS/ (4) //Very NICE (sort + GO)
  1693.  
  1694. http://www.spoj.com/problems/FARIDA/ (3) //Easy & Sympatic ((u+1) | Price+(u+2))
  1695.  
  1696. http://www.spoj.com/problems/AU7_5/ (2) //EASY: dyn(n-1)+dyn(n-k-1)
  1697.  
  1698. http://www.spoj.com/problems/NAIVELOK/ (4) //NICE [depalindromisation]
  1699.  
  1700. http://codeforces.com/contest/846/problem/C (4) //With print
  1701.  
  1702. http://www.spoj.com/problems/CNT_LUCK/ (4) //Number (binary) dp [NICE] {ull care 0-1}
  1703.  
  1704. http://www.spoj.com/problems/MAY99_4/ (3) //Almost combinatoric Sub and 0/1,1/0
  1705.  
  1706. http://www.spoj.com/problems/GEEKOUNT/ (4) //Number dp
  1707.  
  1708. http://www.spoj.com/problems/MUTDNA/ (4) // N*2 (turned?) [not sure if grd poss.]
  1709.  
  1710. http://www.spoj.com/problems/RIOI_3_2/ (5) //VERY NICE (easy imple &mdash; Number Theory thinking)
  1711.  
  1712. http://www.spoj.com/problems/MAXWOODS/ (3) //NICE [EASY][GRID]
  1713.  
  1714. http://www.spoj.com/problems/DIEHARD/ (3) //Easy &mdash; prolly solvable by greedy (but dp is easier)
  1715.  
  1716. http://www.spoj.com/problems/DCEPC810/ (4) //VERY VERY NICE &mdash; Subsequence 2pointers+2bools
  1717.  
  1718. http://www.spoj.com/problems/EQ2/ (4) //NICE: Digit + Carry (from back) &mdash; iff-party
  1719.  
  1720. http://www.spoj.com/problems/DCEPC501/ (3) //NICE & EASY
  1721.  
  1722. http://www.spoj.com/problems/NUMTSN/ (4) //NICE &mdash; Thinking or Opti
  1723.  
  1724. http://www.spoj.com/problems/GONE/ (4) //NICE & EASY [digits]
  1725.  
  1726. http://www.spoj.com/problems/RAONE/ (4) //NICE & EASY [digits] &mdash; almost similar as above
  1727.  
  1728. http://www.spoj.com/problems/STRSEQ/ (4) //VERY VERY NICE &mdash; Next-Function
  1729.  
  1730. http://www.spoj.com/problems/MYQ8/ (4) //VERY NICE &mdash; 3x3 tic-tac-toe [implementation]
  1731.  
  1732. http://codeforces.com/contest/859/problem/C (3) //Easy+Sympathic [PrefixSumOptional]
  1733.  
  1734. http://codeforces.com/contest/859/problem/D (4) //NICE [Probabilities]
  1735.  
  1736. http://www.spoj.com/problems/UNICA/ (4) //VERY NICE [Posibilities][Print][Classical]
  1737.  
  1738. http://www.spoj.com/problems/KOPC12H/ (4) //NICE Digit-DP
  1739.  
  1740. http://www.spoj.com/problems/DRACULA/ (4) //NICE Digit-DP (Both sides) &mdash; iterate by sum
  1741.  
  1742. http://www.spoj.com/problems/ABCPATH/ (3) //DP over dfs (maybe without dp works too?)
  1743.  
  1744. http://www.spoj.com/problems/BEHAPPY/ (2) //Easy one &mdash; low constraints
  1745.  
  1746. http://www.spoj.com/problems/STRCOUNT/ (4) //No input (over bits)
  1747.  
  1748. http://codeforces.com/contest/855/problem/B (2) //prolly not even necessary
  1749.  
  1750. http://codeforces.com/contest/855/problem/C (4) //dp on tree
  1751.  
  1752. http://codeforces.com/contest/855/problem/E (5) //VERY NICE &mdash; Digits & Bitmask & Query (learning!)
  1753.  
  1754. http://www.spoj.com/problems/PAINTWAL/ (6) //VERY NICE &mdash; Imho hard (opti could beat)
  1755.  
  1756. http://www.spoj.com/problems/ADFRUITS/ (3) //Very simple (substring == subsequence)
  1757.  
  1758. http://www.spoj.com/problems/MAIN113/ (2) //NICE but somehow too low constraints
  1759.  
  1760. http://www.spoj.com/problems/MAIN112/ (4) //NICE &mdash; Bitmask
  1761.  
  1762. http://codeforces.com/contest/864/problem/E (5) //VERY NICE &mdash; Sort
  1763.  
  1764. http://www.spoj.com/problems/NOVICE63/ (4) //NICE -On digits (binary)
  1765.  
  1766. http://www.spoj.com/problems/TUG/ (3) //NICE + Observation {N>100 == YES}
  1767.  
  1768. http://www.spoj.com/problems/DOMINO1/ (4) //Used map to solve it
  1769.  
  1770. http://www.spoj.com/problems/NY10E/ (2) //Easy dp
  1771.  
  1772. http://www.spoj.com/problems/MAIN72/ (3) //Easy knapsack
  1773.  
  1774. http://www.spoj.com/problems/NOVICE43/ (2) //Unbelievably low constraints
  1775.  
  1776. http://codeforces.com/contest/598/problem/E (4) //N^5 strategy works fine [VERY NICE]
  1777.  
  1778. http://www.spoj.com/problems/CHAIR/ (3) //Maybe combinatorics too?
  1779.  
  1780. http://www.spoj.com/problems/ACPC10D/ (3) //NICE &mdash; DAG traversal
  1781.  
  1782. http://www.spoj.com/problems/CPCRC1C/ (4) //Digits dp (return pair)
  1783.  
  1784. http://www.spoj.com/problems/BORW/ (3) //Inc+Dec sequence (small array)
  1785.  
  1786. http://codeforces.com/problemset/problem/16/E (5) //Bitmask [NICE]
  1787.  
  1788. http://codeforces.com/problemset/problem/18/E (5) //VERY NICE {no need for second iteration}
  1789.  
  1790. http://codeforces.com/contest/2/problem/B (5) //NICE &mdash; 2/5 are in-fact independent
  1791.  
  1792. http://codeforces.com/contest/4/problem/D (3) //Classical [FW works too] XY > xy
  1793.  
  1794. http://codeforces.com/contest/6/problem/D (4) //NICE (N^4)
  1795.  
  1796. http://codeforces.com/contest/321/problem/E (7) //VERY NICE &mdash; D&C Trick
  1797.  
  1798. http://codeforces.com/contest/868/problem/F (8) //VERY VERY NICE D&C Trick &mdash; With MO Principal
  1799.  
  1800. http://codeforces.com/contest/8/problem/C (5) //NICE &mdash; Masks [N*2^N]
  1801.  
  1802. http://codeforces.com/contest/868/problem/E (8) //VERY NICE &mdash; HARD &mdash; on tree
  1803.  
  1804. http://codeforces.com/contest/10/problem/D (4) //LCIS [NICE]
  1805.  
  1806. http://codeforces.com/contest/13/problem/C (5) //NICE [sorting][only elements from array]
  1807.  
  1808. http://codeforces.com/contest/17/problem/C (5) //[NICE][iterative-sparse][+idea]
  1809.  
  1810. http://codeforces.com/contest/19/problem/B (4) //Knapsack (after good look)
  1811.  
  1812. http://codeforces.com/contest/30/problem/C (4) //Probabilities + (slight)GEO
  1813.  
  1814. http://codeforces.com/contest/31/problem/E (4) //[NICE]
  1815.  
  1816. http://codeforces.com/contest/41/problem/D (4) //With printing
  1817.  
  1818. </spoiler>
  1819.  
  1820. <spoiler summary="dsu">
  1821.  
  1822. http://www.spoj.com/problems/ADABRANC/
  1823.  
  1824. https://www.spoj.com/problems/CONSEC/ (4) //[NICE][OFFLINE]
  1825.  
  1826. https://codeforces.com/gym/102006/problem/C (4) //[NICE][BRUTE-FORCE]
  1827.  
  1828. http://codeforces.com/gym/101962/problem/J (5) //[VERY NICE][TREE-FAT][SPARSE]
  1829.  
  1830. http://codeforces.com/contest/915/problem/F (6) //[VERY NICE][SORTING]
  1831.  
  1832. http://codeforces.com/contest/141/problem/E (6) //[NICE][SPANNIG TREE]
  1833.  
  1834. 7903 - Pandaria (7) //[VERY NICE][DSU][SORTING][MERGE][DFS]
  1835.  
  1836. http://codeforces.com/contest/110/problem/E (4) //[NICE][COMBINATORICS][TREE]
  1837.  
  1838. http://codeforces.com/contest/90/problem/E (5) //[NICE][DSU-LIKE-LINKS][SIMULATION]
  1839.  
  1840. http://codeforces.com/contest/87/problem/D (5) //[VERY NICE][SORTING][COMPRES][DFS]
  1841.  
  1842. http://codeforces.com/contest/884/problem/E (5) //[VERY NICE][MEMORY SPARSE]
  1843.  
  1844. http://codeforces.com/contest/60/problem/D (6) //[NICE][Pythagorean Triples][Gen over max!]
  1845.  
  1846. UVA 10947
  1847.  
  1848. UVA 12363
  1849.  
  1850. LA 3833
  1851.  
  1852. http://codeforces.com/problemset/problem/742/D //+DP
  1853.  
  1854. UVA 10178
  1855.  
  1856. http://codeforces.com/contest/723/problem/F 7
  1857.  
  1858. 13153 UVA (5)
  1859.  
  1860. 13169 UVA (3)
  1861.  
  1862. 11987 UVA (3)
  1863.  
  1864. 11474 UVA (4)
  1865.  
  1866. http://www.spoj.com/problems/BTCODE_G/
  1867.  
  1868. http://codeforces.com/problemset/problem/691/D
  1869.  
  1870. Gym 101174K [2016-2017 ACM-ICPC Southwestern European Regional Programming Contest (SWERC 2016)]
  1871.  
  1872. UVA 10583
  1873.  
  1874. LightOJ 1003
  1875.  
  1876. http://codeforces.com/problemset/problem/731/C
  1877.  
  1878. UVA 793
  1879.  
  1880. UVA 11966
  1881.  
  1882. https://www.codechef.com/problems/COZIC
  1883.  
  1884. 3939 [LA]
  1885.  
  1886. UVA 11503
  1887.  
  1888. http://codeforces.com/problemset/problem/755/C
  1889.  
  1890. UVA 1395
  1891.  
  1892. http://codeforces.com/contest/687/problem/D 6
  1893.  
  1894. http://codeforces.com/contest/680/problem/E 7 //+precalculation/brute force
  1895.  
  1896. http://codeforces.com/contest/766/problem/D 5
  1897.  
  1898. http://www.spoj.com/problems/LEXSTR/ (3) //Nice na stringu
  1899.  
  1900. http://codeforces.com/contest/805/problem/C 3 //NICE (dijkstra like :P)
  1901.  
  1902. http://www.spoj.com/problems/IITKWPCI/ (3) //VERY NICE
  1903.  
  1904. http://www.spoj.com/problems/FRNDCIRC (3) //Classical DSU (NICE for practice)
  1905.  
  1906. http://www.spoj.com/problems/FOXLINGS/ (3) Easy &mdash; just renumbering
  1907.  
  1908. http://www.spoj.com/problems/NITTROAD/ (4) //Process from back
  1909.  
  1910. http://www.spoj.com/problems/SHAHBG/ (2) //DSU not needes (simulated by array)
  1911.  
  1912. http://codeforces.com/contest/598/problem/D (3) //Can be solved with DFS too
  1913.  
  1914. http://codeforces.com/contest/9/problem/E (4) //Making one big cycle
  1915.  
  1916. http://codeforces.com/contest/25/problem/D (4) //Could be done linear too
  1917.  
  1918. http://codeforces.com/contest/28/problem/B (4) //NICE [imho bad statement]
  1919.  
  1920. http://codeforces.com/contest/876/problem/D (4) //DSU adjacent + visited
  1921.  
  1922. http://codeforces.com/contest/875/problem/F (6) //NICE &mdash; Maximum cactus-forest [kruskal-like]
  1923.  
  1924. </spoiler>
  1925.  
  1926. <spoiler summary="euler_function">
  1927.  
  1928. http://codeforces.com/gym/101879/problem/C (6) //[VERY NICE][DFS]
  1929.  
  1930. http://codeforces.com/contest/907/problem/F (7) //[MAGIC]
  1931.  
  1932. UVA 10299
  1933.  
  1934. UVA 10990
  1935.  
  1936. https://www.codechef.com/problems/SMPLSUM
  1937.  
  1938. https://www.codechef.com/problems/COZIE
  1939.  
  1940. http://www.spoj.com/problems/LCMSUM/
  1941.  
  1942. Gym 100975F [2003-2004 Petrozavodsk Summer Training Camp, Saratov SU Contest]
  1943.  
  1944. UVA 13132
  1945.  
  1946. http://www.spoj.com/problems/GCDEX/
  1947.  
  1948. UVA 12995
  1949.  
  1950. http://www.spoj.com/problems/TIP1/
  1951.  
  1952. UVA 11327
  1953.  
  1954. LightOJ 1007
  1955.  
  1956. http://www.spoj.com/problems/ETF/
  1957.  
  1958. Project Euler #72: Counting fractions
  1959.  
  1960. http://www.spoj.com/problems/DCEPCA03/
  1961.  
  1962. http://www.spoj.com/problems/NAJPWG/ 4 //Gauss-Euler
  1963.  
  1964. http://www.spoj.com/problems/DCEPC12G/ (5) //Do what is written there
  1965.  
  1966. http://www.spoj.com/problems/INVPHI/ (5) //Inverse euler
  1967.  
  1968. </spoiler>
  1969.  
  1970. <spoiler summary="euler_tour">
  1971.  
  1972. https://codeforces.com/gym/102006/problem/H (4) //[SORTING][OBSERVATION]
  1973.  
  1974. http://codeforces.com/gym/101650 [I](5) //[NICE][GRAPHS]// Theory is useful
  1975.  
  1976. 13246 - Chained Words (4) //[NICE][LEXICOGRAPHICAL]
  1977.  
  1978. UVA 10735
  1979.  
  1980. http://codeforces.com/contest/789/problem/D //Adj EG + Self/everything
  1981.  
  1982. http://codeforces.com/contest/21/problem/D (5) //[NICE][EulerTour+DP]
  1983.  
  1984. http://codeforces.com/contest/36/problem/E (6) //VERY NICE [4odd is hardest]
  1985.  
  1986. </spoiler>
  1987.  
  1988. <spoiler summary="factorization">
  1989.  
  1990. http://www.spoj.com/problems/ADAHW/ [RHO][Number Theory]
  1991.  
  1992. http://www.spoj.com/problems/ADADIGIT/ [Permutations]
  1993.  
  1994. https://www.spoj.com/problems/PRIMEP/ (5) //[VERY NICE][SEGMENT][BS][SIEVE]
  1995.  
  1996. https://codeforces.com/gym/101981 [J] (4) //[NICE][DIVIDE]
  1997.  
  1998. http://codeforces.com/gym/101801 [B] (3)
  1999.  
  2000. UVA 13067
  2001.  
  2002. Project Euler #108: Diophantine reciprocals I
  2003.  
  2004. http://www.spoj.com/problems/CHGROOM/
  2005.  
  2006. Gym 101370A [2009-2010 Summer Petrozavodsk Camp, Petr Mitrichev Contest 5]
  2007.  
  2008. http://codeforces.com/problemset/problem/837/E
  2009.  
  2010. http://www.spoj.com/problems/PSYCHOT/
  2011.  
  2012. http://www.spoj.com/problems/FACTDIV/
  2013.  
  2014. http://www.spoj.com/problems/NOSQ/
  2015.  
  2016. http://www.spoj.com/problems/FCDC/
  2017.  
  2018. http://www.spoj.com/problems/NFACTOR/
  2019.  
  2020. http://www.spoj.com/problems/ABA12D/
  2021.  
  2022. http://www.spoj.com/problems/PSTR/
  2023.  
  2024. http://www.spoj.com/problems/AMR11E/
  2025.  
  2026. http://www.spoj.com/problems/FACT1/
  2027.  
  2028. http://www.spoj.com/problems/FACT2/
  2029.  
  2030. https://www.hackerearth.com/problem/algorithm/gold-at-lolympics/
  2031.  
  2032. 12005 UVA (7)
  2033.  
  2034. 12062 UVA (6)
  2035.  
  2036. 11960 UVA (3)
  2037.  
  2038. http://www.spoj.com/problems/FACTCG2/ (3)
  2039.  
  2040. http://www.spoj.com/problems/FACT0/ (4)
  2041.  
  2042. http://codeforces.com/contest/546/problem/D 5
  2043.  
  2044. http://codeforces.com/contest/222/problem/C 6
  2045.  
  2046. http://www.spoj.com/problems/COMDIV/ 3
  2047.  
  2048. http://www.spoj.com/problems/SINEGGS/ 3
  2049.  
  2050. http://www.spoj.com/problems/BDOI16B/ 4
  2051.  
  2052. http://www.spoj.com/problems/HG/ 4 //Map == OK
  2053.  
  2054. 11099 UVA (3) //factor + recursion
  2055.  
  2056. 13194 UVA (3) //factorize+generate /or just check
  2057.  
  2058. 13191 UVA (6) //Pollard-Rho
  2059.  
  2060. http://codeforces.com/contest/818/problem/E (4) // Efficient + Two Pointers
  2061.  
  2062. http://codeforces.com/contest/831/problem/F (6) //MAGIC
  2063.  
  2064. http://codeforces.com/contest/839/problem/D (4) // Combinatorics + IE
  2065.  
  2066. http://www.spoj.com/problems/SAS002/ (5) //Find all divisors (big numbers)
  2067.  
  2068. http://www.spoj.com/problems/GCDS/ (4) //Lowest unused prime
  2069.  
  2070. http://www.spoj.com/problems/IITKWPCF/ (4) //Nonprime divisors of N/2
  2071.  
  2072. http://codeforces.com/contest/851/problem/D (4) //Properties of GCD + factor: NICE
  2073.  
  2074. http://www.spoj.com/problems/PTIME/ (3) //Low bounds &mdash; check each prime independently
  2075.  
  2076. http://www.spoj.com/problems/MAIN12B/ (3) //NICE [Factorization][Sort][Unique]
  2077.  
  2078. http://www.spoj.com/problems/AMR11E/ (2) //2664 is the biggest
  2079.  
  2080. http://www.spoj.com/problems/GCPC11A/ (4) //Very nice &mdash; factorize + divide N by powers
  2081.  
  2082. http://www.spoj.com/problems/AMR10C/ (3) //Maximum of factor-powers
  2083.  
  2084. </spoiler>
  2085.  
  2086. <spoiler summary="fenwick">
  2087.  
  2088. http://www.spoj.com/problems/ADABEHIVE/ [2D]
  2089.  
  2090. http://www.spoj.com/problems/ADACABAA/ [2D][Sparse]
  2091.  
  2092. https://codeforces.com/contest/1191/problem/F (5) //[NICE][SORTING]Or similar DS
  2093.  
  2094. https://codeforces.com/gym/102001/problem/H (4) //[NICE][GREEDY]
  2095.  
  2096. https://toph.co/p/easy-prime (4) //[EASY][SIEVE]
  2097.  
  2098. https://toph.co/p/mario-and-princess-peach (5) //[NICE][DP][SEGMENT TREE][MAX]
  2099.  
  2100. http://codeforces.com/gym/101628/problem/B (5) //[NICE][SPARSE][STL]
  2101.  
  2102. http://codeforces.com/gym/100112 (4) [B] //[NICE][INVERSION][OBSERVATION]
  2103.  
  2104. http://codeforces.com/gym/101982 (7) [I] //[VERY NICE][INVERSION][OBSERVATION]
  2105.  
  2106. http://codeforces.com/gym/101908/problem/C (4) //[MATH][INVERSION]
  2107.  
  2108. http://codeforces.com/gym/101889 (5) //[NICE] normalize
  2109.  
  2110. DevSkills-422: Double Pairs (4) //[NICE] normalize
  2111.  
  2112. 7591 - Distribution Center (4) //[NICE][SORTING]
  2113.  
  2114. http://codeforces.com/contest/903/problem/D (5) //[NICE][BIG]
  2115.  
  2116. http://codeforces.com/contest/102/problem/D (4) //[NICE][+DP][NORMALIZE]
  2117.  
  2118. http://codeforces.com/gym/101047/problem/J [2D]
  2119.  
  2120. http://www.spoj.com/problems/MATSUM/ [2D]
  2121.  
  2122. https://www.hackerearth.com/practice/data-structures/advanced-data-structures/fenwick-binary-indexed-trees/practice-problems/algorithm/counting-in-byteland/ [3D]
  2123.  
  2124. https://devskill.com/CodingProblems/ViewProblem/300
  2125.  
  2126. http://codeforces.com/contest/707/problem/E 7 [2D]
  2127.  
  2128. http://codeforces.com/contest/749/problem/E 8
  2129.  
  2130. http://codeforces.com/problemset/gymProblem/101055/D 5 [2D]
  2131.  
  2132. 11240 UVA (4)
  2133.  
  2134. http://codeforces.com/contest/459/problem/D (4) //[NICE][SWEEPING]
  2135.  
  2136. http://codeforces.com/contest/61/problem/E (4) //[NICE][CLASSICAL][2*FW][NORMALIZE]
  2137.  
  2138. http://codeforces.com/contest/669/problem/E 5 //fenwicks &mdash; sparse
  2139.  
  2140. http://codeforces.com/contest/777/problem/E 4 //MAXIMUM
  2141.  
  2142. http://www.spoj.com/problems/TULIPNUM/ 4 //inc &mdash; 1 nor+num|sum(A[B],A[E])
  2143.  
  2144. http://codeforces.com/contest/799/problem/C 3 //MAX FW (but possibly easier?)
  2145.  
  2146. http://codeforces.com/contest/831/problem/E 4 //MAP to get ORDER &mdash; FW == LIST
  2147.  
  2148. http://www.spoj.com/problems/SAS001/ (4) //Nice &mdash; number of inversions + 2P
  2149.  
  2150. http://www.spoj.com/problems/TPGA/ (4) //NICE &mdash; Lesser*(N-i-1)!
  2151.  
  2152. http://www.spoj.com/problems/SGIFT/ (4) //BS works too
  2153.  
  2154. http://www.spoj.com/problems/SUMSUM/ (5) //Bit-by-Bit cnt 0/1
  2155.  
  2156. http://www.spoj.com/problems/AKVQLD03/ (3) //Classical fenwick &mdash; easy
  2157.  
  2158. http://www.spoj.com/problems/ZIGZAG2/ (6) //Very nice &mdash; FW + BS + DP
  2159.  
  2160. http://codeforces.com/contest/849/problem/E (7) //2D Fenwick / ST+TP [NICE]
  2161.  
  2162. http://www.spoj.com/problems/CRAYON/ (5) //VERY NICE [2*FW &mdash; begin + end]
  2163.  
  2164. http://www.spoj.com/problems/NITT8/ (4) //Norm. + Store indices in MAX-Fenwick [REVERSE] [VERY NICE]
  2165.  
  2166. http://www.spoj.com/problems/DCEPC705/ (4) //NICE! Sort + Fenwick
  2167.  
  2168. http://www.spoj.com/problems/DCEPC206/ (3) //NICE & EASY <or many other approaches>
  2169.  
  2170. http://www.spoj.com/problems/KOPC12G/ (4) //N Fenwick trees
  2171.  
  2172. http://www.spoj.com/problems/TRIPINV/ (4) //2xFenwick (triples counting)
  2173.  
  2174. http://codeforces.com/contest/597/problem/C (4) //[VERY NICE] 11*Fenwick
  2175.  
  2176. http://codeforces.com/contest/12/problem/D (4) //NICE [triplet-comparing][sort]
  2177.  
  2178. https://www.spoj.com/problems/NARHIL/ // Sugested by [user:ak07]
  2179.  
  2180. </spoiler>
  2181.  
  2182. <spoiler summary="fft">
  2183.  
  2184. http://www.spoj.com/problems/ADAMATCH/
  2185.  
  2186. https://toph.co/p/play-the-lottery (7) //[VERY NICE][D&C][MODULAR]
  2187.  
  2188. UVA 12633
  2189.  
  2190. 6886 &mdash; Golf Bot [LA]
  2191.  
  2192. http://www.spoj.com/problems/POLYMUL/en/
  2193.  
  2194. Gym 100960C [2015-2016 Petrozavodsk Winter Training Camp, Nizhny Novgorod SU Contest]
  2195.  
  2196. https://www.codechef.com/problems/APRPS
  2197.  
  2198. https://www.codechef.com/problems/POLYEVAL
  2199.  
  2200. http://www.spoj.com/problems/TSUM/ 5
  2201.  
  2202. 13182 UVA 5 //ACTG hamming
  2203.  
  2204. http://codeforces.com/contest/827/problem/E (8) //MAGIC
  2205.  
  2206. http://www.spoj.com/problems/MAXMATCH/ 5 //abc hamming
  2207.  
  2208. </spoiler>
  2209.  
  2210. <spoiler summary="flow">
  2211.  
  2212. https://www.spoj.com/problems/DISGRAPH/ (5) //Stoer-Wagner [global]
  2213.  
  2214. https://codeforces.com/gym/101981 [I] (4) //[NICE]
  2215.  
  2216. http://codeforces.com/gym/101982 [E] (5) //[VERY NICE][GRID]
  2217.  
  2218. http://codeforces.com/gym/101845/problem/F (4) //Basic
  2219.  
  2220. http://codeforces.com/gym/101908/problem/G (4) //[NICE][MATCHING][BS]
  2221.  
  2222. http://www.spoj.com/problems/FASTFLOW/en/ //Raw (no sauce)
  2223.  
  2224. http://codeforces.com/contest/78/problem/E (5) //NICE [Matching-like][+BFS]
  2225.  
  2226. 4322 — Destroying the bus stations (Live Archive)
  2227.  
  2228. 11380 — Down Went The Titanic (UVA) //Interesting grid problem
  2229.  
  2230. 6395 — Surely You Congest (LA) //VERY NICE [slightly advanced]
  2231.  
  2232. 7204 — Blood groups (LA)
  2233.  
  2234. http://codeforces.com/gym/100963 (Flame of Nucleus — F)
  2235.  
  2236. 11167 — Monkeys in the Emei Mountain //Also harder (imho)
  2237.  
  2238. http://codeforces.com/problemset/problem/653/D (+BS)
  2239.  
  2240. 13000 — VIP Treatment (+BS)
  2241.  
  2242. 1242 — Necklace
  2243.  
  2244. https://www.deadline24.pl/assets/problemsets/dl24.elim.2017.B.en.pdf (DEADLINE 24 problem — not sure if it can be submited :O)
  2245.  
  2246. 3487 — Duopoly (Near matching)
  2247.  
  2248. http://codeforces.com/problemset/problem/727/D
  2249.  
  2250. http://codeforces.com/problemset/problem/704/D [Also advanced]
  2251.  
  2252. 5418 — A Plug for UNIX (LA)
  2253.  
  2254. 4957 — Fake scoreboard (LA) //If I remember well, other solutions was also possible
  2255.  
  2256. 1155 — Power Transmission (LOJ) //(classical)
  2257.  
  2258. https://www.codechef.com/problems/ROBOTDAG //Ford-Fukherson
  2259.  
  2260. 10804 — Gopher Strategy (UVA)
  2261.  
  2262. 11506 — Angry Programmer (UVA) //Nodes division
  2263.  
  2264. 10511 — Councilling (UVA)
  2265.  
  2266. 563 — Crimewave
  2267.  
  2268. 1306 — The K-League (UVA)
  2269.  
  2270. 1345 — Jamie's Contact Groups
  2271.  
  2272. 10092 — The Problem with the Problem Setter
  2273.  
  2274. Problem B. Roller Coaster Scheduling (GCJ — 2017)
  2275.  
  2276. 259 — Software Allocation (UVA)
  2277.  
  2278. 5905 — Pool construction (LA) //Imho harder
  2279.  
  2280. 10480 — Sabotage
  2281.  
  2282. http://codeforces.com/contest/808/problem/F 6 //NICE &mdash; nontrivial (max matching with bigger flows)
  2283.  
  2284. http://codeforces.com/contest/847/problem/J 6 //Probably not flows &mdash; matching-like
  2285.  
  2286. </spoiler>
  2287.  
  2288. <spoiler summary="flow-matching-like">
  2289.  
  2290. http://www.spoj.com/problems/ADAHOSE/ [DUAL-GRAPH]
  2291.  
  2292. http://codeforces.com/contest/903/problem/G (6) //[VERY NICE][SEG-TREE][CUT]
  2293.  
  2294. 3837 [LA] //Stable Marriage
  2295.  
  2296. UVA 1175 //Stable Marriage
  2297.  
  2298. 11594 — All Pairs Maximum Flow (UVA)
  2299.  
  2300. http://www.spoj.com/problems/ADABLOOM/ //Maximum matching in general graph
  2301.  
  2302. 11439 — Maximizing the ICPC //Maximum matching in general graph
  2303.  
  2304. 1376 — Animal Run //Max flow on planar graph (Dual == shortest path over edges)
  2305.  
  2306. 10989 — Bomb, Divide and Conquer //Stoer-Wagner — global cut
  2307.  
  2308. </spoiler>
  2309.  
  2310. <spoiler summary="floyd-warshall">
  2311.  
  2312. https://codeforces.com/contest/1204/problem/C (4) //[DP] Nice but hard statement
  2313.  
  2314. https://codeforces.com/contest/1202/problem/B (3) //[VERY NICE]
  2315.  
  2316. http://codeforces.com/gym/101845/problem/C
  2317.  
  2318. https://www.urionlinejudge.com.br/judge/en/problems/view/2676 (3) //simple FW
  2319.  
  2320. 10724 UVA
  2321.  
  2322. UVA 117
  2323.  
  2324. http://codeforces.com/problemset/problem/21/D
  2325.  
  2326. UVA 1198
  2327.  
  2328. LightOJ 1086 //+DP
  2329.  
  2330. http://www.spoj.com/problems/INGRED/ //+DP
  2331.  
  2332. UVA 10048
  2333.  
  2334. UVA 125
  2335.  
  2336. Gym 101223C [2017 Facebook Hacker Cup, Round 1] //+DP
  2337.  
  2338. LightOJ 1221
  2339.  
  2340. UVA 423
  2341.  
  2342. UVA 12179 //+DP
  2343.  
  2344. UVA 1416
  2345.  
  2346. UVA 1233
  2347.  
  2348. UVA 10793
  2349.  
  2350. 10099 UVA
  2351.  
  2352. UVA 869
  2353.  
  2354. LightOJ 1174
  2355.  
  2356. http://www.spoj.com/problems/ARBITRAG/ //Other algos shall work too
  2357.  
  2358. 13211 UVA (5) //NICE &mdash; FW adding states
  2359.  
  2360. http://www.spoj.com/problems/ROHAAN/ (3) //Classical
  2361.  
  2362. http://codeforces.com/contest/25/problem/C (4) //Adding new edges .. need FW principal
  2363.  
  2364. http://codeforces.com/contest/33/problem/B (3) //NICE [dijkstra could work too]
  2365.  
  2366. </spoiler>
  2367.  
  2368. <spoiler summary="friedvaldAlgorithm">
  2369.  
  2370. http://www.spoj.com/problems/ADAPOWER/
  2371.  
  2372. 4956 [LA]
  2373.  
  2374. </spoiler>
  2375.  
  2376. <spoiler summary="game_theory">
  2377.  
  2378. http://www.spoj.com/problems/ADAGAME/ [DP]
  2379.  
  2380. http://www.spoj.com/problems/ADAGAME2/
  2381.  
  2382. http://www.spoj.com/problems/ADAGAME4/
  2383.  
  2384. http://www.spoj.com/problems/ADAQUBIC/
  2385.  
  2386. http://www.spoj.com/problems/ADAFIMBR/
  2387.  
  2388. http://www.spoj.com/problems/ADAGAME5/
  2389.  
  2390. http://www.spoj.com/problems/ADAXMAS/
  2391.  
  2392. https://codeforces.com/contest/1194/problem/D (4) //[OBSERVATIO][PATTERN]
  2393.  
  2394. https://codeforces.com/contest/1191/problem/E (4) //[NICE][IF][OBSERVATION]
  2395.  
  2396. https://www.spoj.com/problems/HUSGAME/ (4) //[VERY NICE][OBSERVATION][RECURSION]
  2397.  
  2398. https://www.spoj.com/problems/IBIGAME/ (5) //[VERY NICE][OBSERVATION][DP]
  2399.  
  2400. https://codeforces.com/gym/101981 [A] (4)
  2401.  
  2402. https://codeforces.com/gym/102058/problem/F (4) //[NICE]
  2403.  
  2404. http://codeforces.com/gym/101801 [F] (3) //[EASY][OBSERVATION][NIM]
  2405.  
  2406. http://codeforces.com/gym/101908/problem/B (5) //[NICE][NIMBERS][OBSERVATION]
  2407.  
  2408. http://codeforces.com/gym/101873 [H] (5) //[VERY NICE][OBSERVATION][TREE] //LUP LUP
  2409.  
  2410. http://codeforces.com/gym/101808/problem/I (5) //[DP][OBSERVATION]
  2411.  
  2412. http://codeforces.com/contest/919/problem/F (6) //[NICE][HARD][IMPLE][BFS][TOPO][GRAF]
  2413.  
  2414. http://codeforces.com/contest/918/problem/D (4) //[NICE][DAG][DP][TREE]
  2415.  
  2416. http://codeforces.com/contest/914/problem/B (3) //[NICE][EASY][OBSERVATION][PARITY]
  2417.  
  2418. http://codeforces.com/contest/148/problem/D (4) //[EASY][DP][PROBABILITY]
  2419.  
  2420. http://codeforces.com/contest/138/problem/D (7) //[VERY NICE][DP][OBSERVATION]
  2421.  
  2422. https://arc087.contest.atcoder.jp/tasks/arc087_c (5) //[VERY NICE][TRIE][SEQUENCE]
  2423.  
  2424. http://codeforces.com/contest/120/problem/E (3) //[NICE][SYMETRY][PARITY]
  2425.  
  2426. http://codeforces.com/contest/88/problem/E (5) //[VERY NICE][PREFIX-XOR][NIMBERS][SQRT][MATH]
  2427.  
  2428. http://codeforces.com/contest/69/problem/D (4) //[NICE][DP] Reflection can be ignored
  2429.  
  2430. http://codeforces.com/contest/55/problem/C (4) //[NICE] Size of piece from border
  2431.  
  2432. http://codeforces.com/problemset/problem/255/E --MEX
  2433.  
  2434. https://devskill.com/CodingProblems/ViewProblem/91
  2435.  
  2436. https://devskill.com/CodingProblems/ViewProblem/364
  2437.  
  2438. Project Euler #96: Su Doku //Sudoku
  2439.  
  2440. 11859 UVA 4
  2441.  
  2442. 11863 UVA 4
  2443.  
  2444. 11892 UVA 3 //Probably solved by many
  2445.  
  2446. 11534 UVA 5
  2447.  
  2448. http://www.spoj.com/problems/VECTAR11/ 4 //Nsqrt(N) passes [with break]
  2449.  
  2450. http://codeforces.com/contest/768/problem/E (4) //NICE &mdash; Grundy
  2451.  
  2452. http://www.spoj.com/problems/SYNC13C/ (4) //2*DP {maybe not seeing sth}
  2453.  
  2454. http://codeforces.com/contest/787/problem/C (4)
  2455.  
  2456. http://codeforces.com/contest/794/problem/C (3) //Find optimal strategy: choose back/front
  2457.  
  2458. http://codeforces.com/contest/794/problem/E (5) //NICE Find stategy: Even/Odd
  2459.  
  2460. http://codeforces.com/contest/812/problem/E (7) //Advanced NIM strategy
  2461.  
  2462. http://www.spoj.com/problems/GAMEMVS/ (4) //Nimbers (Ai^X)<=Ai
  2463.  
  2464. http://www.spoj.com/problems/PLAYGAME/ (3) //Check pattern
  2465.  
  2466. http://www.spoj.com/problems/CHAOS_CC/ (4) //VERY NICE [nimbers]
  2467.  
  2468. http://codeforces.com/contest/851/problem/E (5) //Very nice [nimbers] [bitset]
  2469.  
  2470. http://www.spoj.com/problems/CHGROOM/ (4) //+Factorisation [NICE & Easy]: Win unless 2 prime factors
  2471.  
  2472. http://www.spoj.com/problems/EALP1/ (4) //NICE ~ Possible Moves of NIM
  2473.  
  2474. http://www.spoj.com/problems/GAME3/ (4) //VERY NICE &mdash; pattern watching [A145812]
  2475.  
  2476. http://www.spoj.com/problems/GAME2/ (5) //VERY NICE &mdash; https://community.topcoder.com/tc?module=Static&d1=match_editorials&d2=srm338 (CAKE)
  2477.  
  2478. http://www.spoj.com/problems/CF36D/ (5) //Pattern watching (care for 1)
  2479.  
  2480. http://codeforces.com/contest/15/problem/C (4) //VERY NICE [XOR: A,1,A+1,0..repeat]
  2481.  
  2482. http://codeforces.com/contest/39/problem/E (4) //Slightly [DP][MATH][ROUNDING]
  2483.  
  2484. http://codeforces.com/contest/63/problem/E (5) //[NICE][BITMASK-DP]
  2485.  
  2486. </spoiler>
  2487.  
  2488. <spoiler summary="gauss">
  2489.  
  2490. 12910 &mdash; Snakes and Ladders [UVA]
  2491.  
  2492. UVA 10828
  2493.  
  2494. http://codeforces.com/gym/100923/problem/C
  2495.  
  2496. 4963 [LA]
  2497.  
  2498. UVA 12849
  2499.  
  2500. Gym 100962A [2015-2016 Petrozavodsk Winter Training Camp, Moscow SU Trinity Contest][NICE]
  2501.  
  2502. UVA 10109 [NICE][HARD-WORK]
  2503.  
  2504. </spoiler>
  2505.  
  2506. <spoiler summary="geometry">
  2507.  
  2508. http://www.spoj.com/problems/ADAPICK/
  2509.  
  2510. http://www.spoj.com/problems/ADAKOHL/
  2511.  
  2512. https://codeforces.com/gym/102307/problem/A (7)
  2513.  
  2514. https://codeforces.com/contest/1199/problem/B (2) //[NICE][SIMPLE]
  2515.  
  2516. https://codeforces.com/gym/101991/problem/J (5)
  2517.  
  2518. https://codeforces.com/gym/101991/problem/B (4)
  2519.  
  2520. https://codeforces.com/gym/102006/problem/I (4) //[VERY NICE][ITERATIVE]
  2521.  
  2522. https://codeforces.com/gym/102021 [G] (8) //[3D]
  2523.  
  2524. https://codeforces.com/gym/102021 [B] (5) //Path on circle
  2525.  
  2526. https://codeforces.com/gym/102058/problem/K (3) //[BRUTE-FORCE][FAIL]
  2527.  
  2528. https://codeforces.com/gym/101972/problem/C (4) //[EASY][POINTS DISTANCE][IMAGE]
  2529.  
  2530. http://codeforces.com/gym/101628/problem/C (4) //Circles intersection
  2531.  
  2532. http://codeforces.com/gym/100112 [G] (4) //Special cases and so on - imple.
  2533.  
  2534. http://codeforces.com/gym/101982 [G] (3) //[DISTANCE]
  2535.  
  2536. http://codeforces.com/gym/101845/problem/D (5) //[VERY NICE][POLYGON][MO]
  2537.  
  2538. http://codeforces.com/gym/101962/problem/G (5) //Angles
  2539.  
  2540. http://codeforces.com/gym/101908/problem/K
  2541.  
  2542. http://codeforces.com/gym/101879/problem/A (7)
  2543.  
  2544. http://codeforces.com/gym/101873 [G] (4) //Pick's Theorem
  2545.  
  2546. http://codeforces.com/gym/101873 [A] (6) //heavy implementation
  2547.  
  2548. http://codeforces.com/gym/101808/problem/E (5)
  2549.  
  2550. http://codeforces.com/gym/101808/problem/A (2)
  2551.  
  2552. http://codeforces.com/gym/101666 [A] (4)
  2553.  
  2554. http://codeforces.com/gym/101726/problem/J (5) //[NICE][INTERSECTION][DS]
  2555.  
  2556. http://codeforces.com/gym/101650 [F] (6) //Polygons + circles
  2557.  
  2558. http://codeforces.com/gym/101650 [H] (2) //A few if's
  2559.  
  2560. http://codeforces.com/contest/908/problem/C (3)
  2561.  
  2562. http://codeforces.com/contest/140/problem/A (3) //Circles around bigger circle
  2563.  
  2564. http://codeforces.com/contest/136/problem/D (4) //+Brute-Force
  2565.  
  2566. http://codeforces.com/contest/127/problem/A (1) //Points distance
  2567.  
  2568. http://codeforces.com/gym/101597/problem/B (3) //Simply brute-force just the closest to points
  2569.  
  2570. http://codeforces.com/contest/70/problem/D (5) //Dynamic Convex Hull
  2571.  
  2572. https://icpc.kattis.com/problems/airport //Proposed by [user:tautsjasiunsas]
  2573.  
  2574. https://www.hackerrank.com/contests/world-codesprint-7/challenges/elastic-rope/problem
  2575.  
  2576. https://devskill.com/CodingProblems/ViewProblem/20 [EASY]
  2577.  
  2578. UVA 10321 //Polygon intersection
  2579.  
  2580. UVA 11265 //Polygon point +/-
  2581.  
  2582. UVA 13112 //Polygon
  2583.  
  2584. 10907 UVA [Area of polygon from a point]
  2585.  
  2586. 3378 &mdash; Swamp Things [LA] &mdash; Maximum points on line
  2587.  
  2588. UVA 11768 //Discrete points
  2589.  
  2590. 2542 [LA] //Arc size [formula]
  2591.  
  2592. UVA 1571 //As below [easier]
  2593.  
  2594. https://www.codechef.com/problems/ALLPOLY //[NICE] Point seeing polygon
  2595.  
  2596. http://www.spoj.com/problems/IITKWPCL/ //Point distance
  2597.  
  2598. UVA 11281 //circle~triangle
  2599.  
  2600. UVA 12921 //circle reconstruction
  2601.  
  2602. UVA 190 //circle from 3 points
  2603.  
  2604. UVA 12240 //pts>circle
  2605.  
  2606. UVA 438 //circle pt
  2607.  
  2608. LightOJ 1018 //Minimum # of lines through all pts [VERY NICE]
  2609.  
  2610. UVA 11008 //Similar as above
  2611.  
  2612. UVA 12830 //Biggest rectangle without points inside
  2613.  
  2614. UVA 11012 //Most distant points
  2615.  
  2616. UVA 1683 //Closest points
  2617.  
  2618. UVA 12389 //3D MH Closest Points
  2619.  
  2620. http://www.spoj.com/problems/AMR12C/ //Pt closest to all other points
  2621.  
  2622. http://www.spoj.com/problems/CLOPPAIR/ //Closest pair of points
  2623.  
  2624. UVA 10678 //Circles intersection
  2625.  
  2626. http://codeforces.com/problemset/problem/600/D //Circles intersection
  2627.  
  2628. LightOJ 1118 //Circles intersection
  2629.  
  2630. http://www.spoj.com/problems/CERC07C/en/ //Bounding circle
  2631.  
  2632. UVA-10005 //Bounding circle
  2633.  
  2634. 2407 [LA] //Bounding Sphere
  2635.  
  2636. LightOJ 1120 //Rectangle's Union
  2637.  
  2638. LightOJ 1130 //Circle x Rectangle intersection
  2639.  
  2640. UVA 11177 //Circle x Convex Polygon
  2641.  
  2642. http://codeforces.com/problemset/problem/610/D //Lines intersections (axes parallel)
  2643.  
  2644. 6263 [LA] //Pt in areas
  2645.  
  2646. LightOJ 1058 //# parallelograma
  2647.  
  2648. UVA 12931 //Common area of polygons
  2649.  
  2650. UVA 10301 //Intersecting circles
  2651.  
  2652. UVA 453 //Circles intersection
  2653.  
  2654. http://codeforces.com/problemset/problem/681/E //Circles intersection
  2655.  
  2656. UVA 920 //Lines intersecion (etc..)
  2657.  
  2658. UVA 12556
  2659.  
  2660. http://codeforces.com/problemset/problem/793/C //Intersection ans similar
  2661.  
  2662. UVA 11343 //Intersection of segments
  2663.  
  2664. UVA 866 //Intersection of segments
  2665.  
  2666. Gym 100190I [2011 ACM-ICPC East Central North America (ECNA 2011)] //Segment intersection
  2667.  
  2668. http://codeforces.com/gym/100917/problem/K
  2669.  
  2670. UVA 11686 //Segment intersection
  2671.  
  2672. LightOJ 1388
  2673.  
  2674. UVA 833 //Segment intersection
  2675.  
  2676. LightOJ 1196 //Points sides
  2677.  
  2678. UVA 10167 //Points sides
  2679.  
  2680. UVA 12818 //Arc & Point distance
  2681.  
  2682. http://www.spoj.com/problems/SICRANO/ //Point-line distance
  2683.  
  2684. http://codeforces.com/problemset/problem/614/C //Point-line distance
  2685.  
  2686. UVA 13117 //Point-line distance
  2687.  
  2688. UVA 12483 //Point-line distance
  2689.  
  2690. UVA 12173 //Point-line distance
  2691.  
  2692. UVA 10075 //Point distance on sphere
  2693.  
  2694. https://www.hackerrank.com/contests/booking-hackathon/challenges/nearby-attractions/problem //Pt sphr
  2695.  
  2696. UVA 535 //Point distance on sphere
  2697.  
  2698. UVA 10897 //Sphere tavelling
  2699.  
  2700. UVA 11817 //Sphere travelling
  2701.  
  2702. UVA 10316 //Sphere travelling
  2703.  
  2704. UVA 1469 //Fractions distance 3D
  2705.  
  2706. 11930
  2707.  
  2708. 12173 UVA 3
  2709.  
  2710. 12194 UVA 4
  2711.  
  2712. 11894 UVA 3
  2713.  
  2714. 11769 UVA 7
  2715.  
  2716. 11665 UVA 5
  2717.  
  2718. 11509 UVA 4
  2719.  
  2720. 11355 UVA 5
  2721.  
  2722. 11265 UVA 6 //Nice one | polygon &mdash; cut/pt-check/area
  2723.  
  2724. 11123 UVA 4 //Counting trapezoids
  2725.  
  2726. 11177 UVA 6 //BS+Polygon/Circle intersection
  2727.  
  2728. 11186 UVA 3
  2729.  
  2730. 11008 UVA 5 //with DP → #intersected triangles
  2731.  
  2732. 11012 UVA 5 //Nejvzdálenější body (Manhatton 3D)
  2733.  
  2734. 11072 UVA 4 //Points v poly gonu
  2735.  
  2736. http://codeforces.com/problemset/problem/682/E 6 (biggest triangle)
  2737.  
  2738. http://codeforces.com/contest/672/problem/C 4 //easy &mdash; just think it up
  2739.  
  2740. http://codeforces.com/contest/667/problem/A 2 //vzorecky
  2741.  
  2742. http://codeforces.com/contest/793/problem/C 5 //EASY but beware of epsilons (NICE)
  2743.  
  2744. http://codeforces.com/contest/794/problem/B 2 //Can be done with BS
  2745.  
  2746. http://codeforces.com/contest/814/problem/D 5 //+DP on trees (NICE &mdash; but low geom.)
  2747.  
  2748. 10750 UVA 3 //Closest points &mdash; try all pairs
  2749.  
  2750. http://codeforces.com/contest/820/problem/B 3 //Polygon angle find!
  2751.  
  2752. 13213 UVA 5 //VERY NICE &mdash; Voronoi diagram (low constraints so not actually needed)
  2753.  
  2754. 13215 UVA 3 //EASY &mdash; Sum areas and find side lengths
  2755.  
  2756. http://www.spoj.com/problems/IITKWPCC/ (5) //VERY VERY NICE &mdash; Nqrt(N)log(N)
  2757.  
  2758. http://www.spoj.com/problems/NNS/ (5) Closest points query [fake geometry] {__128}[NICE]
  2759.  
  2760. http://codeforces.com/contest/849/problem/B (3) //X-Product &mdash; side
  2761.  
  2762. http://www.spoj.com/problems/AMR12C/ (5) //Point closest to all other points (with speed)
  2763.  
  2764. http://www.spoj.com/problems/SICRANO/ (3) //Line-Point distance
  2765.  
  2766. http://www.spoj.com/problems/VCIRCLES/ (5) //Heavy geometrical ****
  2767.  
  2768. http://www.spoj.com/problems/CIRU/ (5) //Same as above [yet bigger constraints]
  2769.  
  2770. http://www.spoj.com/problems/THREETW1/ (4) //Fermat point search
  2771.  
  2772. http://www.spoj.com/problems/CLOPPAIR/ (4) //Closest pair of points
  2773.  
  2774. http://www.spoj.com/problems/MAXLN/ (2) //Some basic (4*r^2+.25)
  2775.  
  2776. http://www.spoj.com/problems/KOLICA/ (4) //VERY NICE [nasty iff party]
  2777.  
  2778. http://codeforces.com/contest/598/problem/C (4) //NICE ~ Precision! [ld]
  2779.  
  2780. http://codeforces.com/contest/18/problem/A (2) //EASY&FINE: Pythagoreas
  2781.  
  2782. http://codeforces.com/contest/40/problem/A (2) //[EASY][DISTANCE]
  2783.  
  2784. </spoiler>
  2785.  
  2786. <spoiler summary="graph">
  2787.  
  2788. https://codeforces.com/contest/1182/problem/D (5) //[CENTRUM][OBSERVATION][DFS]
  2789.  
  2790. https://www.urionlinejudge.com.br/judge/en/problems/view/1562 (5) //[VERY NICE][QUEUE][GREEDY]
  2791.  
  2792. https://codeforces.com/gym/102001/problem/G (4) //[NICE][BS]
  2793.  
  2794. https://codeforces.com/gym/102006/problem/G (4) //[NICE][TOPOSORT][OBSERVATION]
  2795.  
  2796. https://codeforces.com/gym/102058/problem/B (6) //[VERY NICE][REVERSE-SIMULATION]
  2797.  
  2798. http://codeforces.com/gym/101666 [H] (6) //[VERY NICE][GEOMETRY][DSU][EULER][PLANAR]
  2799.  
  2800. 2827 [LA] //3Coloring
  2801.  
  2802. 2243 [LA] //3Coloring
  2803.  
  2804. 5603 [LA] //Coloring
  2805.  
  2806. UVA 1658 //Shortest paths
  2807.  
  2808. UVA 12821 //Shortest paths
  2809.  
  2810. http://codeforces.com/contest/27/problem/D (5)
  2811.  
  2812. 11387 (UVA) 4
  2813.  
  2814. http://www.spoj.com/problems/VFRIEND2/ (5) //Graph possible check
  2815.  
  2816. http://codeforces.com/contest/859/problem/E (4) //VERY NICE (2 cases: CYCLE [x2] / TREE [x(Size+1)]
  2817.  
  2818. http://codeforces.com/contest/847/problem/C (2) //Forest making Easy&Nice
  2819.  
  2820. http://codeforces.com/contest/863/problem/C (3) //Cycle in states
  2821.  
  2822. </spoiler>
  2823.  
  2824. <spoiler summary="greedy">
  2825.  
  2826. https://codeforces.com/contest/1207/problem/B (3) //[NICE][EASY][IMPLE]
  2827.  
  2828. https://codeforces.com/contest/1204/problem/B (2) //[OBSERVE][MATH]
  2829.  
  2830. https://codeforces.com/contest/1148/problem/E (5) //[NICE][SORTING][STL]
  2831.  
  2832. https://codeforces.com/contest/1175/problem/D (4) //[NICE][PREPROCESS][SORTING]
  2833.  
  2834. https://codeforces.com/contest/1203/problem/F1 (5) //[VERY NICE][SORTING][CASES]
  2835.  
  2836. https://codeforces.com/contest/1176/problem/C (3) //[SIMPLE][NICE][IMPLE]
  2837.  
  2838. https://codeforces.com/contest/1176/problem/A (1)
  2839.  
  2840. https://codeforces.com/contest/1200/problem/B (3) //[SIMPLE][NICE]
  2841.  
  2842. https://codeforces.com/contest/1202/problem/A (2)
  2843.  
  2844. https://codeforces.com/contest/1181/problem/B (4) //[BIG]
  2845.  
  2846. https://atcoder.jp/contests/abc136/tasks/abc136_c (3) //[REVERSE]
  2847.  
  2848. https://codeforces.com/contest/1185/problem/C2 (4)
  2849.  
  2850. https://codeforces.com/contest/1185/problem/B (2) //[EASY]
  2851.  
  2852. https://codeforces.com/contest/1180/problem/B (3) //[IMPLEMENTATION][MATH]
  2853.  
  2854. https://codeforces.com/contest/1186/problem/D (4) //[IMPLEMENTATION]
  2855.  
  2856. https://codeforces.com/contest/1197/problem/B (3) //[BITONIC][IMPLE]
  2857.  
  2858. https://www.spoj.com/problems/DIVSTR/ (3) //[CUTE]
  2859.  
  2860. https://codeforces.com/gym/101981 [E] (5) //[NICE][NORMALIZE][STACK]
  2861.  
  2862. https://codeforces.com/gym/102001/problem/L (3) //[BITS]
  2863.  
  2864. https://toph.co/p/passwords (2)
  2865.  
  2866. http://codeforces.com/gym/100112 (3) //[FINE]
  2867.  
  2868. http://codeforces.com/gym/101666 (4) //[NICE][QUEUE][DFS][EVENTS]
  2869.  
  2870. http://codeforces.com/gym/101806/problem/T (5) //[NICE][SEGMENT TREE][SORTING]
  2871.  
  2872. http://codeforces.com/contest/916/problem/B (3) //[BITS] FIRST & LAST
  2873.  
  2874. http://codeforces.com/contest/913/problem/C (3) //+[DP]
  2875.  
  2876. http://codeforces.com/contest/146/problem/D (4) //[NICE][CONSTRUCTION]
  2877.  
  2878. http://codeforces.com/contest/146/problem/C (3) //[EASY][NICE][TWO-CASES]
  2879.  
  2880. http://codeforces.com/contest/139/problem/D (4) //Muchas cases
  2881.  
  2882. 7887 - Back to the Future (4) //[NICE][2*HEAP]
  2883.  
  2884. http://codeforces.com/contest/910/problem/A (2) //DP works too
  2885.  
  2886. http://codeforces.com/contest/125/problem/D (4) //Limited possibilities
  2887.  
  2888. http://codeforces.com/contest/902/problem/A (2) //Just keep last
  2889.  
  2890. http://codeforces.com/contest/898/problem/D (4) //[NICE][FENWICK/OR/PREFIX]
  2891.  
  2892. http://codeforces.com/contest/118/problem/C (4) //[NICE] - Try each digit (iterate in waves)
  2893.  
  2894. 7706 - Pokemons (2) //Sweep and keep maximum
  2895.  
  2896. http://codeforces.com/contest/893/problem/D (4) //[NICE][SWEEP][MAXIMUM] - pay max when have to
  2897.  
  2898. http://codeforces.com/contest/892/problem/B (2) //Sweep from back
  2899.  
  2900. http://codeforces.com/contest/102/problem/C (3) //sort by frequency
  2901.  
  2902. https://devskill.com/CodingProblems/ViewProblem/419 (2) //Sweep from back
  2903.  
  2904. http://codeforces.com/contest/890/problem/C (3) //frequence
  2905.  
  2906. http://codeforces.com/contest/890/problem/B (2) //[EASY][REVERSE]
  2907.  
  2908. http://codeforces.com/contest/888/problem/B (2) //Equalize U/D and L/R
  2909.  
  2910. http://codeforces.com/gym/101597/problem/J (4) //[NICE][SWEEP]
  2911.  
  2912. http://codeforces.com/contest/76/problem/B (4) //[NICE][MATCHING-LIKE][2PTRS]
  2913.  
  2914. http://codeforces.com/contest/73/problem/B (4) //[IMPLEMENTATION][SORTING]
  2915.  
  2916. http://codeforces.com/contest/883/problem/K (4) //Nice - Two sweeps
  2917.  
  2918. http://codeforces.com/contest/49/problem/D (3) //NICE - 1010101 OR 0101010 [haming]
  2919.  
  2920. http://codeforces.com/contest/58/problem/C (4) //NICE - group trees by slopes
  2921.  
  2922. http://codeforces.com/contest/729/problem/D 3
  2923.  
  2924. http://codeforces.com/contest/729/problem/E 4
  2925.  
  2926. http://codeforces.com/contest/725/problem/D 4
  2927.  
  2928. http://codeforces.com/contest/725/problem/F 9
  2929.  
  2930. http://codeforces.com/contest/732/problem/E 5
  2931.  
  2932. http://codeforces.com/contest/727/problem/F 6
  2933.  
  2934. http://codeforces.com/contest/724/problem/D 5
  2935.  
  2936. http://codeforces.com/contest/723/problem/C 4
  2937.  
  2938. http://codeforces.com/contest/719/problem/B 2
  2939.  
  2940. http://codeforces.com/contest/712/problem/C 3
  2941.  
  2942. 13152 UVA (4)
  2943.  
  2944. http://codeforces.com/contest/746/problem/E 5
  2945.  
  2946. http://codeforces.com/contest/746/problem/D 3
  2947.  
  2948. http://codeforces.com/contest/749/problem/C 3
  2949.  
  2950. 11737 UVA (3)
  2951.  
  2952. 11786 UVA (4)
  2953.  
  2954. 11630 UVA (5)
  2955.  
  2956. 11563 UVA (4)
  2957.  
  2958. 11491 UVA (4)
  2959.  
  2960. 11330 UVA (3)
  2961.  
  2962. 11089 UVA (2)
  2963.  
  2964. http://codeforces.com/contest/884/problem/D (4) //PQ or Sort
  2965.  
  2966. http://www.spoj.com/problems/SQRMINSUM/ 3 //solve-able in O(N+M)-arrayqueue
  2967.  
  2968. http://www.spoj.com/problems/MSCHED/ 3 //sweep from back
  2969.  
  2970. http://www.spoj.com/status/ns=18780683 4 //all perm + A<B<C works
  2971.  
  2972. http://www.spoj.com/problems/NINJA7/ (3) //sort by diff
  2973.  
  2974. http://www.spoj.com/problems/NINJA2/ (4) //try all possib. (26)
  2975.  
  2976. http://codeforces.com/contest/767/problem/E (6)
  2977.  
  2978. http://codeforces.com/contest/637/problem/B (3) //NICE pro prvaky
  2979.  
  2980. http://codeforces.com/contest/777/problem/B (3) // -||-
  2981.  
  2982. http://codeforces.com/contest/777/problem/D (3) //just go from end
  2983.  
  2984. http://codeforces.com/contest/779/problem/C (3) //NICE pro prváky
  2985.  
  2986. http://www.spoj.com/problems/SPCU/ (2) //Easy &mdash; zamysleni (max int = index)
  2987.  
  2988. http://www.spoj.com/problems/LOPOV/ (4) //sort + queue (or just queue) NICE
  2989.  
  2990. http://codeforces.com/contest/792/problem/E (5) //T%S<=T/S + check proper
  2991.  
  2992. http://codeforces.com/contest/807/problem/E (5) //NICE &mdash; put asice P2 / rest &mdash; greedy from small
  2993.  
  2994. http://codeforces.com/contest/799/problem/E (5) //Many queues &mdash; but NICE
  2995.  
  2996. http://codeforces.com/contest/808/problem/C (3) //EASY
  2997.  
  2998. http://codeforces.com/contest/802/problem/B (4) //Priority by "next"
  2999.  
  3000. 10850 UVA (4) //Queue a brute-force
  3001.  
  3002. http://codeforces.com/contest/813/problem/A (1) //Zahrivacka pro prvaky
  3003.  
  3004. 10716 UVA (4) //NICE &mdash; always find closest pair
  3005.  
  3006. http://codeforces.com/contest/816/problem/C (3) //NICE &mdash; greater<lesser side
  3007.  
  3008. http://codeforces.com/contest/820/problem/D (5) //VERY NICE &mdash; O(N) -~- 5 events per number
  3009.  
  3010. http://codeforces.com/contest/818/problem/B (2) //Zahrivacka pro prvaky
  3011.  
  3012. http://codeforces.com/contest/822/problem/C (4) //Almost classical Sort+Queue
  3013.  
  3014. http://codeforces.com/contest/825/problem/C (2) //Nice & Easy
  3015.  
  3016. http://codeforces.com/contest/825/problem/D (3) //Update by modulo
  3017.  
  3018. http://codeforces.com/contest/835/problem/B (2) // Zahhrivacka pro prvaky
  3019.  
  3020. http://codeforces.com/contest/839/problem/B (3) //Nasty iffs &mdash; yet nice excersize
  3021.  
  3022. http://www.spoj.com/problems/PCPC12I/ (4) //Swipe MINIMUM from left/right [10^6-A[i] trick]
  3023.  
  3024. http://www.spoj.com/problems/AMR12I/ (3) //NICE a) MAX_SEG>=K b) (SEG_SIZE-1)/K+1
  3025.  
  3026. http://www.spoj.com/problems/BUSYMAN/ (2) //NICE&EASY &mdash; Sort + keep minimum
  3027.  
  3028. http://codeforces.com/contest/861/problem/C (3) //2+ but not same
  3029.  
  3030. http://www.spoj.com/problems/WORKB/ (3) //Simple "min" formula for each neighbor
  3031.  
  3032. http://codeforces.com/contest/864/problem/D (4) //VERY NICE &mdash; Frequency + unused
  3033.  
  3034. http://www.spoj.com/problems/ROADTRIP/ (4) //VERY NICE &mdash; Keeping last lesser
  3035.  
  3036. http://codeforces.com/contest/597/problem/B (3) //NICE [Classical]
  3037.  
  3038. http://www.spoj.com/problems/SHLIGHTS/ (4)
  3039.  
  3040. http://www.spoj.com/problems/MLK/ (3) //VERY NICE &mdash; Sum all prefix sums
  3041.  
  3042. http://codeforces.com/contest/867/problem/C (4) //NICE [IMPLE][2POINTERS][MID+EPS]
  3043.  
  3044. http://codeforces.com/contest/867/problem/E (5) //NICE [EASY-IMPLE][HARD-CONS]
  3045.  
  3046. http://codeforces.com/contest/18/problem/D (4) //+Big Integer
  3047.  
  3048. http://codeforces.com/contest/276/problem/D (4) //NICE &mdash; Find first mismatch bit (then 111...111)
  3049.  
  3050. http://codeforces.com/contest/3/problem/B (4) //Divide 1/2 [sort][2pointers]
  3051.  
  3052. http://codeforces.com/contest/3/problem/D (4) //?==) ..if open < 0: set max A-B to (
  3053.  
  3054. http://codeforces.com/contest/26/problem/B (4) // +1 ( | -1 ): -1, erase .. erase sum in the end
  3055.  
  3056. http://codeforces.com/contest/33/problem/A (2) //EASY [long-statement]
  3057.  
  3058. http://codeforces.com/contest/44/problem/E (2) //Try mins then try maxs
  3059.  
  3060. http://codeforces.com/contest/45/problem/D (3) //Priority-queue+'sort'
  3061.  
  3062. </spoiler>
  3063.  
  3064. <spoiler summary="hash">
  3065.  
  3066. http://www.spoj.com/problems/ADACLEAN/
  3067.  
  3068. https://codeforces.com/contest/1200/problem/E (5) //[VERY NICE]
  3069.  
  3070. http://codeforces.com/gym/101808/problem/B (5) //[NICE][NUMBERS]
  3071.  
  3072. http://codeforces.com/gym/101741/problem/K (5) //[NICE][SQRT][PATTERN MATCHING]
  3073.  
  3074. 7979 - Red Rover (3) //[NICE] //Many other ways to solve
  3075.  
  3076. http://codeforces.com/contest/898/problem/F (5) //[VERY NICE]//Hash by 10
  3077.  
  3078. http://codeforces.com/contest/114/problem/D (4) //[NICE] //N^2Log(N) might/might-not be OK
  3079.  
  3080. https://www.urionlinejudge.com.br/judge/en/problems/view/1503 (7) //[NICE][BS][OPTI]
  3081.  
  3082. Gym 101466E [2017 ACM-ICPC, Universidad Nacional de Colombia Programming Contest][NICE]
  3083.  
  3084. 12012 UVA 4
  3085.  
  3086. http://codeforces.com/contest/727/problem/E 7
  3087.  
  3088. http://codeforces.com/contest/718/problem/D 8
  3089.  
  3090. 11855 UVA 4
  3091.  
  3092. http://codeforces.com/contest/752/problem/D 5
  3093.  
  3094. http://codeforces.com/contest/825/problem/F 5 //String + Periods
  3095.  
  3096. http://codeforces.com/contest/835/problem/D 4 //Palindromes
  3097.  
  3098. http://www.spoj.com/problems/CF25E/ (5) //VERY NICE [IMPLE>CONCEPT]
  3099.  
  3100. http://codeforces.com/contest/7/problem/D (4) //Palindromes
  3101.  
  3102. http://codeforces.com/contest/19/problem/C (4) //[NICE]: Not a string
  3103.  
  3104. </spoiler>
  3105.  
  3106. <spoiler summary="hull">
  3107.  
  3108. 13300 - Ghost Hunting (4) //Hull + calipers passes
  3109.  
  3110. http://codeforces.com/gym/101982 [M] (7) //[VERY NICE][HULL][TERNARY]
  3111.  
  3112. http://www.spoj.com/problems/GARDENHU/en/
  3113.  
  3114. 2453 &mdash; Wall [LA]
  3115.  
  3116. UVA 13213
  3117.  
  3118. UVA 11096
  3119.  
  3120. Gym 100792G [2015-2016 ACM-ICPC, NEERC, Moscow Subregional Contest]
  3121.  
  3122. https://www.codechef.com/problems/KTHCON
  3123.  
  3124. http://codeforces.com/problemset/problem/605/C
  3125.  
  3126. UVA 218
  3127.  
  3128. UVA 11072
  3129.  
  3130. 11168 UVA
  3131.  
  3132. UVA 12307
  3133.  
  3134. Gym 100963I [2007-2008 Summer Petrozavodsk Camp, Japanese Contest, 2007-08-29]
  3135.  
  3136. UVA 11243
  3137.  
  3138. UVA 10256
  3139.  
  3140. 109 SCUD Busters
  3141.  
  3142. UVA 13024 [NICE]
  3143.  
  3144. UVA 10002
  3145.  
  3146. Gym 100886H [2015-2016 Petrozavodsk Winter Training Camp, Saratov SU Contest]
  3147.  
  3148. UVA 1139
  3149.  
  3150. UVA 681
  3151.  
  3152. UVA 811
  3153.  
  3154. https://www.codechef.com/problems/MGCHGEOM
  3155.  
  3156. UVA 11769 //3D
  3157.  
  3158. </spoiler>
  3159.  
  3160. <spoiler summary="chess">
  3161.  
  3162. http://www.spoj.com/problems/ADACHESS/
  3163.  
  3164. http://www.spoj.com/problems/ADACHES2/
  3165.  
  3166. http://www.spoj.com/problems/ADAGAME5/
  3167.  
  3168. http://www.spoj.com/problems/ADAXMAS/
  3169.  
  3170. URI 1100 (3) //[BFS][KNIGHT]
  3171.  
  3172. https://www.codechef.com/problems/CHQUEENS (4) //[IMPLEMENTATION]
  3173.  
  3174. http://codeforces.com/contest/131/problem/E (4) //[NICE][STL][SORTING][QUEEN]
  3175.  
  3176. http://codeforces.com/contest/42/problem/B (4) //NICE - Checkmate check
  3177.  
  3178. UVA 10748 //bfs
  3179.  
  3180. LightOJ 1143
  3181.  
  3182. https://www.hackerearth.com/practice/algorithms/greedy/basics-of-greedy-algorithms/practice-problems/algorithm/harry-and-ron-play-a-game-of-chess/
  3183.  
  3184. UVA 10196
  3185.  
  3186. http://www.spoj.com/problems/KNMOVE/
  3187.  
  3188. UVA 11352
  3189.  
  3190. http://www.spoj.com/problems/NAKANJ/ //BFS
  3191.  
  3192. LightOJ 1010
  3193.  
  3194. LightOJ 1171 //MM
  3195.  
  3196. 2883 LA
  3197.  
  3198. UVA 439
  3199.  
  3200. http://www.spoj.com/problems/TRKNIGHT/ //??
  3201.  
  3202. 2308 LA
  3203.  
  3204. http://www.spoj.com/problems/CCHESS/ //Dijkstra
  3205.  
  3206. http://codeforces.com/problemset/problem/630/H //[ROOKS][BIG][COMBINATORICS]
  3207.  
  3208. LightOJ 1005 //As above (but with real rooks)
  3209.  
  3210. LightOJ 1061 //Placing queens
  3211.  
  3212. UVA 11085
  3213.  
  3214. UVA 10094 //Queen placing [NICE][PATTERN]
  3215.  
  3216. https://devskill.com/CodingProblems/ViewProblem/383
  3217.  
  3218. 11852 UVA (6)
  3219.  
  3220. http://www.spoj.com/problems/KLUG1/ (2) //Jumps of horse
  3221.  
  3222. http://www.spoj.com/problems/CODESPTD/ (5) //VERY NICE &mdash; DP [Queens]
  3223.  
  3224. http://codeforces.com/contest/3/problem/A (2) //Imple &mdash; Shortest path for king
  3225.  
  3226. http://codeforces.com/contest/38/problem/B (2) //NICE &mdash; Simple possition checking
  3227.  
  3228. </spoiler>
  3229.  
  3230. <spoiler summary="implementation">
  3231.  
  3232. https://codeforces.com/gym/102302/problem/D (3) //[2Pointers]
  3233.  
  3234. https://codeforces.com/gym/102307/problem/F (4) //[PARSING][PYTHON]
  3235.  
  3236. https://codeforces.com/contest/1207/problem/A (2) //[MIN/MAX][MATH]
  3237.  
  3238. https://codeforces.com/contest/1206/problem/A (2) //[OBSERVATION]
  3239.  
  3240. https://codeforces.com/contest/1148/problem/A (1) //[IF][MATH]
  3241.  
  3242. https://codeforces.com/contest/1203/problem/A (1) //[FOR][IF]
  3243.  
  3244. https://codeforces.com/contest/1173/problem/A (1) //[IF]
  3245.  
  3246. https://devskill.com/CodingProblems/ViewProblem/584 (2)
  3247.  
  3248. https://codeforces.com/contest/1200/problem/A (2) //[EASY]
  3249.  
  3250. https://codeforces.com/contest/1182/problem/B (3) //[PRACTICE][GRID-MOVEMENT]
  3251.  
  3252. https://codeforces.com/contest/1201/problem/B (2)
  3253.  
  3254. https://codeforces.com/contest/1201/problem/A (2)
  3255.  
  3256. https://atcoder.jp/contests/abc136/tasks/abc136_a (1)
  3257.  
  3258. https://codeforces.com/contest/1199/problem/A (2) //[BF]
  3259.  
  3260. https://codeforces.com/contest/1183/problem/A (2)
  3261.  
  3262. https://codeforces.com/contest/1186/problem/A (1)
  3263.  
  3264. https://codeforces.com/contest/1178/problem/A (2)
  3265.  
  3266. https://codeforces.com/contest/1195/problem/A (2) //[ARRAY]
  3267.  
  3268. https://codeforces.com/contest/1191/problem/A
  3269.  
  3270. https://www.spoj.com/problems/MOZHSLM/ (3) //Two sweeps
  3271.  
  3272. https://www.spoj.com/problems/OVGDEL/ (3) //[NICE][EASY][FREQUENCY]
  3273.  
  3274. https://www.spoj.com/problems/VTV1001/ (2)
  3275.  
  3276. https://codeforces.com/gym/102001/problem/D (3)
  3277.  
  3278. https://codeforces.com/gym/102021 (7) //[VERY NICE]Easy thought but nice imple
  3279.  
  3280. https://codeforces.com/gym/101972/problem/E (2)
  3281.  
  3282. https://codeforces.com/gym/101972/problem/D (1) //[IF]
  3283.  
  3284. https://toph.co/p/full-pyramid (1)
  3285.  
  3286. http://codeforces.com/gym/101992/problem/F (2)
  3287.  
  3288. http://codeforces.com/gym/101628/problem/D (3)
  3289.  
  3290. http://codeforces.com/gym/100112 [I] (5) //[NICE][STRINGS][BITMASKS]
  3291.  
  3292. http://codeforces.com/gym/100112 [A] (2)
  3293.  
  3294. http://codeforces.com/gym/101982 [L] (3)
  3295.  
  3296. http://codeforces.com/gym/101982 [J] (2)
  3297.  
  3298. http://codeforces.com/gym/101982 [A] (2) //Easy
  3299.  
  3300. http://codeforces.com/gym/101845/problem/H (2) //Dates
  3301.  
  3302. http://codeforces.com/gym/101801 [L] (1)
  3303.  
  3304. http://codeforces.com/gym/101801 [A] (1)
  3305.  
  3306. http://codeforces.com/gym/101864 [C] (2) //Easy
  3307.  
  3308. http://codeforces.com/gym/101889/my [H] (2)
  3309.  
  3310. http://codeforces.com/contest/934/problem/A (2)
  3311.  
  3312. http://codeforces.com/contest/922/problem/A (2) //Iff-party
  3313.  
  3314. http://codeforces.com/contest/914/problem/A (1)
  3315.  
  3316. http://codeforces.com/contest/916/problem/A (2) //Time
  3317.  
  3318. http://codeforces.com/contest/915/problem/B (2) //Formula / Iff
  3319.  
  3320. http://codeforces.com/contest/915/problem/A (1)
  3321.  
  3322. http://codeforces.com/contest/913/problem/A (1)
  3323.  
  3324. http://codeforces.com/contest/912/problem/A (2) //Easy [corner-cases]
  3325.  
  3326. http://codeforces.com/contest/146/problem/A (1)
  3327.  
  3328. http://www.spoj.com/problems/ESYR/ (1) //Bad one :/
  3329.  
  3330. http://codeforces.com/contest/908/problem/A (1)
  3331.  
  3332. http://codeforces.com/contest/147/problem/A (2) //Parsing
  3333.  
  3334. http://codeforces.com/contest/139/problem/A (1)
  3335.  
  3336. http://codeforces.com/contest/137/problem/A (1)
  3337.  
  3338. 7886 - Assigning Teams (2) //[EASY][SORTING]
  3339.  
  3340. http://codeforces.com/contest/133/problem/A (1)
  3341.  
  3342. http://codeforces.com/contest/134/problem/A (1)
  3343.  
  3344. http://codeforces.com/contest/131/problem/A (1)
  3345.  
  3346. http://codeforces.com/contest/127/problem/B (1) [EASY]
  3347.  
  3348. http://codeforces.com/contest/899/problem/B (2) //Dates
  3349.  
  3350. http://codeforces.com/contest/898/problem/C (3) //No thinking - just implementation
  3351.  
  3352. 6157 How do spiders walk on water? (4) //boring problem
  3353.  
  3354. http://codeforces.com/contest/900/problem/A (1)
  3355.  
  3356. 7613 Relative atomic mass (1)
  3357.  
  3358. http://codeforces.com/contest/122/problem/A (1) //Find all lucky
  3359.  
  3360. http://codeforces.com/contest/120/problem/B (1) //Iteration
  3361.  
  3362. http://codeforces.com/contest/120/problem/A (1) //Iff/Logic
  3363.  
  3364. http://codeforces.com/contest/118/problem/B (2) //[PRINTING]
  3365.  
  3366. http://codeforces.com/contest/108/problem/A (1) //[EASY][PRINT][TIME]
  3367.  
  3368. http://codeforces.com/contest/106/problem/A (1) //Iff-party
  3369.  
  3370. http://codeforces.com/contest/890/problem/A (1) //if or perm
  3371.  
  3372. http://codeforces.com/contest/90/problem/B (2) //No idea - just cycles
  3373.  
  3374. http://codeforces.com/contest/75/problem/A (1) //conversion
  3375.  
  3376. http://codeforces.com/contest/884/problem/B (1) //Simple sum +N-1
  3377.  
  3378. http://codeforces.com/contest/48/problem/A (1) //Very easy [fe. perm]
  3379.  
  3380. http://codeforces.com/contest/51/my (2) //Lex-lowest-string (|s|=4)
  3381.  
  3382. http://codeforces.com/contest/54/problem/A (2) //Single sweep
  3383.  
  3384. http://codeforces.com/contest/719/problem/C 3
  3385.  
  3386. http://codeforces.com/contest/747/problem/E 4
  3387.  
  3388. http://codeforces.com/contest/754/problem/C 5
  3389.  
  3390. 11482 UVA (4)
  3391.  
  3392. 11291 UVA (3)
  3393.  
  3394. 11070 UVA (5) //evaluation of expression
  3395.  
  3396. 11074 UVA (2)
  3397.  
  3398. http://codeforces.com/contest/678/problem/B 2 //calendar days
  3399.  
  3400. http://codeforces.com/contest/643/problem/A 3 //easy &mdash; just simulate
  3401.  
  3402. http://codeforces.com/contest/770/problem/D 5 //easy &mdash; but pain &mdash; draw
  3403.  
  3404. http://codeforces.com/contest/789/problem/B 3 //simulate (mby twice)
  3405.  
  3406. 13171 UVA (1)
  3407.  
  3408. 10800 UVA (3)
  3409.  
  3410. http://codeforces.com/contest/828/problem/B 2 //EASY & NICE &mdash; just analysis
  3411.  
  3412. http://codeforces.com/contest/825/problem/B 2 //EASY & NICE &mdash; Piskvorky &mdash; pro prvaky
  3413.  
  3414. http://codeforces.com/contest/837/problem/B 2 //Just implementation
  3415.  
  3416. http://codeforces.com/contest/837/problem/C 2 //Some nasty iffs
  3417.  
  3418. http://codeforces.com/contest/845/problem/B 2 //Easy pro prvaky
  3419.  
  3420. http://codeforces.com/contest/845/problem/D 3 //Iffs &mdash; folow the rules
  3421.  
  3422. http://www.spoj.com/problems/UNIHW/ 4 //NICE (but many iffs)
  3423.  
  3424. http://codeforces.com/contest/5/problem/A (2) //Parsing
  3425.  
  3426. http://codeforces.com/contest/5/problem/B (3) //Output formating
  3427.  
  3428. http://codeforces.com/contest/6/problem/B (2) //Simply check by adjancecy vector + set
  3429.  
  3430. http://codeforces.com/contest/7/problem/A (1) //Oneinteresting if
  3431.  
  3432. http://codeforces.com/contest/8/problem/B (2) //Sample vectors + set/or/array
  3433.  
  3434. http://codeforces.com/contest/12/problem/A (1) //Find mirror by middle
  3435.  
  3436. http://codeforces.com/contest/16/problem/A (1) //Easy check of chars
  3437.  
  3438. http://codeforces.com/contest/21/problem/A (2) //Easy but nasty iff imple
  3439.  
  3440. http://codeforces.com/contest/31/problem/B (2) //Boring imple
  3441.  
  3442. http://codeforces.com/contest/34/problem/C (3) //Easy string parsing
  3443.  
  3444. http://codeforces.com/contest/41/problem/C (2) //String parsing
  3445.  
  3446. </spoiler>
  3447.  
  3448. <spoiler summary="inclusion-exclusion">
  3449.  
  3450. http://www.spoj.com/problems/KPRIMESB/ (4)
  3451.  
  3452. http://www.spoj.com/problems/IITKWPCH/ (4) //NICE &mdash; on bits
  3453.  
  3454. http://www.spoj.com/problems/SUBSET/ (5) //VERY NICE &mdash; 3^10 (^2 but not exactly) (+ sorting)
  3455.  
  3456. https://www.hackerearth.com/practice/algorithms/dynamic-programming/bit-masking/practice-problems/algorithm/special-pairs-7/description/ (4) //NICE [Brute-force]
  3457.  
  3458. </spoiler>
  3459.  
  3460. <spoiler summary="interactive">
  3461.  
  3462. https://codeforces.com/gym/102307/problem/L (5) //[NICE][BS]
  3463.  
  3464. https://codeforces.com/contest/1207/problem/E (4) //[NICE][SIMPLE][BITS]
  3465.  
  3466. https://codeforces.com/contest/1206/problem/E (5) //[VERY NICE][BRUTE FORCE][DEPENDENCIES]
  3467.  
  3468. https://codeforces.com/contest/1174/problem/F (7) //[VERY NICE][TREE][CONSTRUCTIVE]
  3469.  
  3470. http://codeforces.com/contest/897/problem/D (4) //NICE! Back/Front
  3471.  
  3472. http://codeforces.com/contest/727/problem/C (2)
  3473.  
  3474. http://codeforces.com/contest/810/problem/D (4) //BS * 3 (same)
  3475.  
  3476. http://codeforces.com/contest/811/problem/D (4) //BFS &mdash; easy .. some ifs
  3477.  
  3478. http://codeforces.com/contest/835/problem/E (4) //NICE! Bitsets + Detect + XOR
  3479.  
  3480. http://codeforces.com/contest/844/problem/D (5) //NICE! Randomized algo
  3481.  
  3482. http://codeforces.com/contest/862/problem/D (4) //NICE! Find first + Binary Search
  3483.  
  3484. http://codeforces.com/contest/872/problem/D (4) //NICE! [no clue why it passed]
  3485.  
  3486. </spoiler>
  3487.  
  3488. <spoiler summary="isomorphism">
  3489.  
  3490. https://www.urionlinejudge.com.br/judge/en/problems/view/2652 (4) //Tree isomorphism
  3491.  
  3492. UVA 12489 //Tree
  3493.  
  3494. https://www.hackerrank.com/contests/hourrank-16/challenges/jenny-subtrees/problem
  3495.  
  3496. http://www.spoj.com/problems/DSUBTREE/ (5) //Isomorphism on trees (try all subsets)
  3497.  
  3498. http://www.spoj.com/problems/TREEISO/ (4) //Simple isomorphism of trees
  3499.  
  3500. </spoiler>
  3501.  
  3502. <spoiler summary="josephus">
  3503.  
  3504. http://codeforces.com/gym/101864 [A] (4) //Observation
  3505.  
  3506. UVA 151
  3507.  
  3508. UVA 1394
  3509.  
  3510. UVA 440
  3511.  
  3512. 3803 [LA]
  3513.  
  3514. https://www.urionlinejudge.com.br/judge/en/problems/view/1030
  3515.  
  3516. UVA 12912
  3517.  
  3518. UVA 13114
  3519.  
  3520. 11351 UVA (2)
  3521.  
  3522. http://www.spoj.com/problems/CLSLDR/ (4) //Muchas queries &mdash; go DP
  3523.  
  3524. http://www.spoj.com/problems/WTK/ (Easy) Suggested by [user:ayushgupta1997]
  3525.  
  3526. http://www.spoj.com/problems/DANGER/ (Easy) Suggested by [user:ayushgupta1997]
  3527.  
  3528. http://www.spoj.com/problems/POCRI/ (Medium) Suggested by [user:ayushgupta1997]
  3529.  
  3530. http://www.spoj.com/problems/NG0FRCTN/ (Medium) Suggested by [user:ayushgupta1997]
  3531.  
  3532. </spoiler>
  3533.  
  3534. <spoiler summary="KMP">
  3535.  
  3536. http://www.spoj.com/problems/ADAPET/
  3537.  
  3538. UVA 12604
  3539.  
  3540. UVA 12467
  3541.  
  3542. UVA 11019
  3543.  
  3544. http://www.spoj.com/problems/NAJPF/ (4) //classical kmp &mdash; all patterns
  3545.  
  3546. http://codeforces.com/contest/808/problem/G (6) //with DP -harder
  3547.  
  3548. </spoiler>
  3549.  
  3550. <spoiler summary="lca">
  3551.  
  3552. http://www.spoj.com/problems/ADAAPPLE/ [HLD][LCT works too]
  3553.  
  3554. http://www.spoj.com/problems/ADAVISIT/ [HLD]
  3555.  
  3556. http://www.spoj.com/problems/ADALICI/ [KTH Ancestor &mdash; FAST!]
  3557.  
  3558. http://www.spoj.com/problems/ADAORANG/
  3559.  
  3560. https://www.spoj.com/problems/COWGATH/ (5) //[VERY NICE][EULER][OFFLINE][SEGMENT]
  3561.  
  3562. https://codeforces.com/gym/102021 [A] (5) //[IMPLEMENTATION][LCA]
  3563.  
  3564. http://codeforces.com/gym/101908/problem/L (5) //[NICE][HLD][FW]
  3565.  
  3566. http://codeforces.com/gym/101808/problem/K (5) //[NICE][IMPLEMENTATION][CYCLE]
  3567.  
  3568. http://www.spoj.com/problems/LCA/ //Easiest one &mdash; low constraints [practice]
  3569.  
  3570. http://www.spoj.com/problems/LCASQ/
  3571.  
  3572. http://codeforces.com/contest/916/problem/E (6) //[VERY NICE][SEG-TREE]//REROOT
  3573.  
  3574. http://codeforces.com/contest/911/problem/F (5) //[VERY NICE][LONGEST PATH]
  3575.  
  3576. https://devskill.com/CodingProblems/ViewProblem/141
  3577.  
  3578. UVA 12655
  3579.  
  3580. https://www.codechef.com/problems/PSHTTR
  3581.  
  3582. LightOJ 1162
  3583.  
  3584. Gym 100685G [2012-2013 ACM-ICPC, NEERC, Moscow Subregional Contest]
  3585.  
  3586. UVA 12533
  3587.  
  3588. https://www.codechef.com/problems/CLOSEFAR //But kinda more comples [ST]
  3589.  
  3590. http://codeforces.com/contest/733/problem/F 7
  3591.  
  3592. 11354 UVA (4)
  3593.  
  3594. http://www.spoj.com/problems/POLICEMEN/ (3) //simple + small graph
  3595.  
  3596. http://www.spoj.com/problems/QTREE2/ (5) //very easy if bin. understrood
  3597.  
  3598. http://codeforces.com/contest/828/problem/F 7 // Differently MST / Outside
  3599.  
  3600. http://codeforces.com/contest/832/problem/D (5) //Classical + Depth /OR/ HLD +ST
  3601.  
  3602. http://www.spoj.com/problems/DRTREE/ (5) //NICE [finding ancestor + depths]
  3603.  
  3604. http://codeforces.com/problemset/problem/838/B (6) //VERY NICE [HLD + ET + ST]
  3605.  
  3606. http://www.spoj.com/problems/NTICKETS/ (4) //Maximum on path
  3607.  
  3608. http://www.spoj.com/problems/GRASSPLA/ (5) //HLD
  3609.  
  3610. http://codeforces.com/contest/855/problem/D (4) //VERY VERY BAD STATEMENT (not so bad problem)
  3611.  
  3612. http://codeforces.com/gym/101630 {L}(6) //[NICE][HLD or DSU][XOR] //Parenthessis
  3613.  
  3614. </spoiler>
  3615.  
  3616. <spoiler summary="lcs_subsequence">
  3617.  
  3618. http://www.spoj.com/problems/ADASEED/ [HUNT]
  3619.  
  3620. https://codeforces.com/gym/102307/problem/C (5) //[NICE][4RUS][DP]
  3621.  
  3622. http://www.spoj.com/problems/MC/
  3623.  
  3624. UVA 10192
  3625.  
  3626. UVA 531
  3627.  
  3628. LightOJ 1110
  3629.  
  3630. UVA 12747 //Perm
  3631.  
  3632. http://www.spoj.com/problems/XMEN/ //Perm
  3633.  
  3634. UVA 10405
  3635.  
  3636. UVA 12511 //Increasing
  3637.  
  3638. UVA 10635 //Increasing
  3639.  
  3640. 10949 UVA (6) &mdash; Hunt or Bit
  3641.  
  3642. http://www.spoj.com/problems/MC/ (3) //Classical
  3643.  
  3644. http://www.spoj.com/problems/LCS0/ (7) //Bit
  3645.  
  3646. </spoiler>
  3647.  
  3648. <spoiler summary="lct">
  3649.  
  3650. http://www.spoj.com/problems/ADAROADS/ [ONLINE][UPDATES][LCT]
  3651.  
  3652. http://www.spoj.com/problems/DYNALCA/en/ //DYNAMIC LCA
  3653.  
  3654. http://codeforces.com/gym/100460/problem/C
  3655.  
  3656. http://codeforces.com/gym/100960/problem/H
  3657.  
  3658. http://www.spoj.com/problems/DYNACON1/
  3659.  
  3660. http://codeforces.com/contest/892/problem/E (7) [VERY NICE]//By prices .. LCT
  3661.  
  3662. </spoiler>
  3663.  
  3664. <spoiler summary="lis">
  3665.  
  3666. UVA 231
  3667.  
  3668. UVA 10131
  3669.  
  3670. 2931 LA
  3671.  
  3672. http://www.spoj.com/problems/NDS/
  3673.  
  3674. UVA 481
  3675.  
  3676. http://www.spoj.com/problems/ELIS/
  3677.  
  3678. UVA 497
  3679.  
  3680. UVA 11790
  3681.  
  3682. http://www.spoj.com/problems/ALTSEQ/ 3 //solvable by FW in Nlog(N)
  3683.  
  3684. http://www.spoj.com/problems/VISIBLEBOX/ (4) //with multiset
  3685.  
  3686. http://www.spoj.com/problems/DOSA/ (5)
  3687.  
  3688. http://www.spoj.com/problems/CODERE3/ 3 //Low bounds LIS/LDS
  3689.  
  3690. http://www.spoj.com/problems/BRDGHRD/ 4 //lis (nondecreasing)
  3691.  
  3692. http://www.spoj.com/problems/GONESORT/ 4 //Permutation-lis + riddle statement
  3693.  
  3694. http://codeforces.com/contest/847/problem/B 4 //Multiple Lis's
  3695.  
  3696. http://codeforces.com/contest/67/problem/D (4) //[NICE][DOUBLE REMAP]
  3697.  
  3698. </spoiler>
  3699.  
  3700. <spoiler summary="matching">
  3701.  
  3702. http://www.spoj.com/problems/ADAPATH/
  3703.  
  3704. http://www.spoj.com/problems/ADACITY/
  3705.  
  3706. http://www.spoj.com/problems/ADAPLNTS/
  3707.  
  3708. https://codeforces.com/contest/1198/problem/E (7) //[VERY NICE][HARD][KONIG][OBSERVATION]
  3709.  
  3710. URI 1330 (4) //[NICE][SIMPLE]
  3711.  
  3712. http://codeforces.com/gym/101873 [F] (4)
  3713.  
  3714. http://codeforces.com/gym/101666 [E] (6) //[NICE][GEOMETRY][BINARY SEARCH][PROBABILITY]
  3715.  
  3716. http://www.spoj.com/problems/MATCHING/ //Raw (no sauce)
  3717.  
  3718. http://codeforces.com/contest/116/problem/B (3) //Low cons. Can be done without algo
  3719.  
  3720. 6234 — Tile Cut (LA)
  3721.  
  3722. 10080 — Gopher II (UVA) //Easy — sympathic
  3723.  
  3724. 11419 — SAM I AM (UVA) //Grid-Matching
  3725.  
  3726. http://codeforces.com/gym/101485 (Elementary Math — E) //Very nice principal [not that hard]
  3727.  
  3728. 3673 — Black-White Grid (UVA) //Grid
  3729.  
  3730. 12927 — Points Cover (UVA)
  3731.  
  3732. 6851 — The Programmers (LA)
  3733.  
  3734. 6887 — Book Club //NICE
  3735.  
  3736. 6571 — It Can Be Arranged
  3737.  
  3738. 12530 — Game of Tiles
  3739.  
  3740. http://codeforces.com/gym/100820 (Airport — A) //Nice one
  3741.  
  3742. http://codeforces.com/gym/100753 (Bounty Hunterr II — B) //VERY NICE — I refered multiple times to this principal
  3743.  
  3744. http://codeforces.com/gym/101408 (Cat vs Dog — C)
  3745.  
  3746. 1171 — Knights in Chessboard (II) (LOJ) //Classical chess
  3747.  
  3748. 12644 — Vocabulary
  3749.  
  3750. http://codeforces.com/gym/101047/problem/H
  3751.  
  3752. http://codeforces.com/problemset/problem/659/E
  3753.  
  3754. 12972 — Cuban Challenge (UVA)
  3755.  
  3756. 1201 — Taxi Cab Scheme (UVA)
  3757.  
  3758. 12963 — Astragalus Nitidiflorus
  3759.  
  3760. 6525 — Attacking rooks (LA)
  3761.  
  3762. 3415 — Guardian of Decency (LA)
  3763.  
  3764. 12159 — Gun Fight (UVA)
  3765.  
  3766. https://www.codechef.com/problems/CHEFYODA //Imho matching is not the crucial part here
  3767.  
  3768. 12831 — Bob the Builder
  3769.  
  3770. http://codeforces.com/problemset/problem/831/D
  3771.  
  3772. 11262 — Weird Fence
  3773.  
  3774. 12549 — Sentry Robots
  3775.  
  3776. 11138 — Nuts and Bolts
  3777.  
  3778. http://codeforces.com/contest/727/problem/D 4
  3779.  
  3780. 11985 UVA (5)
  3781.  
  3782. http://www.spoj.com/problems/AMR12A/ (5) //VERY NICE [goophers + bonus] (BS)
  3783.  
  3784. http://www.spoj.com/problems/NITT4/ (4) //VERY NICE [Chessboard matching]
  3785.  
  3786. http://www.spoj.com/problems/SCPC11H/ (4)//NICE &mdash; Match those which fits inside
  3787.  
  3788. </spoiler>
  3789.  
  3790. <spoiler summary="matrix">
  3791.  
  3792. 12045 UVA (4)
  3793.  
  3794. </spoiler>
  3795.  
  3796. <spoiler summary="matrix_exponentiation">
  3797.  
  3798. http://www.spoj.com/problems/ADAMONEY/
  3799.  
  3800. UVA 13298 - A Fibonacci Family Formula (4) //[NICE][CLASSICAL]
  3801.  
  3802. http://codeforces.com/gym/101628/problem/I (4) //[MODULAR][NICE][TRANSITION]
  3803.  
  3804. http://codeforces.com/gym/101845/problem/A
  3805.  
  3806. 13284 Macarons (4) //[NICE][BITMASK][DP] Classical
  3807.  
  3808. http://codeforces.com/contest/147/problem/B (5) //[NICE][BS][GRAPHS]
  3809.  
  3810. http://codeforces.com/contest/107/problem/D (5) //[NICE][DP]
  3811.  
  3812. UVA 12653
  3813.  
  3814. LightOJ 1131
  3815.  
  3816. UVA &mdash; 12470
  3817.  
  3818. http://codeforces.com/problemset/problem/696/D
  3819.  
  3820. https://www.hackerrank.com/contests/mathemagic-bits/challenges/gp-on-fibonacci-matrix [accesable?]
  3821.  
  3822. https://www.hackerrank.com/contests/mathemagic-bits/challenges/degree-diameter-on-trees [accesable?]
  3823.  
  3824. LightOJ 1052
  3825.  
  3826. https://www.codechef.com/problems/KBIGNUMB
  3827.  
  3828. LightOJ 1160
  3829.  
  3830. LightOJ 1096
  3831.  
  3832. UVA 11486
  3833.  
  3834. http://codeforces.com/problemset/problem/718/C
  3835.  
  3836. LightOJ 1070
  3837.  
  3838. LightOJ 1132
  3839.  
  3840. http://codeforces.com/problemset/problem/621/E
  3841.  
  3842. Project Euler #114: Counting block combinations I
  3843.  
  3844. http://codeforces.com/problemset/problem/821/E
  3845.  
  3846. UVA 12593
  3847.  
  3848. https://www.codechef.com/AUG16/problems/SHAIKHGN //Not exactly but similar principle
  3849.  
  3850. 11551 UVA (4)
  3851.  
  3852. 11486 UVA (5)
  3853.  
  3854. 10743 UVA (5) //A001169 [easy multi / hard to come with recurence]
  3855.  
  3856. http://codeforces.com/contest/821/problem/E (6) //Not trivial to come-up with matrix
  3857.  
  3858. http://www.spoj.com/problems/DCEPCA06/ (4) //NICE &mdash; 10x10 matrix
  3859.  
  3860. http://www.spoj.com/problems/GSWORDS/ (3) //NICE&EASY &mdash; 3-states "OO,OX,XO"
  3861.  
  3862. http://www.spoj.com/problems/TETRAHRD/ (4) //Easy + Sum
  3863.  
  3864. http://www.spoj.com/problems/NACCI/ (4) //Classical (N-Bonacci)
  3865.  
  3866. http://www.spoj.com/problems/JZPCIR/ (5) //VERY NICE: A137726
  3867.  
  3868. </spoiler>
  3869.  
  3870. <spoiler summary="mcmf">
  3871.  
  3872. http://www.spoj.com/problems/ADAGROW/
  3873.  
  3874. http://www.spoj.com/problems/ADAFEAR/
  3875.  
  3876. https://www.urionlinejudge.com.br/judge/en/problems/view/1617 (4) //[BASIC]
  3877.  
  3878. 13288 - Cordon Bleu (6) //[NICE][MATCHING]
  3879.  
  3880. http://codeforces.com/gym/100800 (Aqueduct Construction — A)
  3881.  
  3882. 10806 — Dijkstra, Dijkstra.
  3883.  
  3884. 12944 — Earthquake Disaster
  3885.  
  3886. 12891 — Risk of Trading
  3887.  
  3888. https://www.codechef.com/problems/HOGON
  3889.  
  3890. http://codeforces.com/contest/863/problem/F (5) //VERY NICE
  3891.  
  3892. 11613 UVA (6)
  3893.  
  3894. http://codeforces.com/contest/802/problem/C (8) //Nice but hard to see + negative
  3895.  
  3896. http://codeforces.com/contest/802/problem/N (5) //Easy but faster MCMF needed
  3897.  
  3898. http://codeforces.com/contest/818/problem/G (6) //NICE + MUCH Faster MCMF
  3899.  
  3900. http://www.spoj.com/problems/BNMT/ (7) //VERY NICE (some optimalisations needed + weird data set)
  3901.  
  3902. http://codeforces.com/contest/884/problem/F (6) //Alphabetical buckets
  3903.  
  3904. </spoiler>
  3905.  
  3906. <spoiler summary="median">
  3907.  
  3908. http://codeforces.com/contest/713/problem/C 7
  3909.  
  3910. http://www.spoj.com/problems/RMID2/ 4
  3911.  
  3912. http://www.spoj.com/problems/RMID/ 3 (as above just not so dynamic)
  3913.  
  3914. http://www.spoj.com/problems/EC_ESTA/ 4 //classical dynamic median
  3915.  
  3916. http://www.spoj.com/problems/DCEPCA09/ (6) //VERY NICE [MO +++ MEDIAN, MEAN, FREQ]
  3917.  
  3918. </spoiler>
  3919.  
  3920. <spoiler summary="meet_in_middle">
  3921.  
  3922. https://codeforces.com/gym/102307/problem/H (6) //[VERY NICE][RECURSION][BS]
  3923.  
  3924. http://codeforces.com/contest/912/problem/E (5) //[VERY NICE][BS][2P][PRIMES]
  3925.  
  3926. http://codeforces.com/contest/888/problem/E (4) //NICE[EASY]
  3927.  
  3928. http://codeforces.com/contest/51/problem/E (6) //NICE[GRAPH][Cycles of length 5]
  3929.  
  3930. https://devskill.com/CodingProblems/ViewProblem/245
  3931.  
  3932. https://devskill.com/CodingProblems/ViewProblem/256
  3933.  
  3934. 11851 UVA (5)
  3935.  
  3936. 11465 UVA (5)
  3937.  
  3938. 13207 UVA (4) //Straight-forward MIM
  3939.  
  3940. http://www.spoj.com/problems/COLOR_CC/ (4) //VERY NICE &mdash; div by partity (take lesser) → 8^6
  3941.  
  3942. </spoiler>
  3943.  
  3944. <spoiler summary="MO">
  3945.  
  3946. http://www.spoj.com/problems/ADAUNIQ/ [Updates]
  3947.  
  3948. http://www.spoj.com/problems/ADANUM/
  3949.  
  3950. http://www.spoj.com/problems/ADAPEAR/
  3951.  
  3952. http://www.spoj.com/problems/ADAPHONE/
  3953.  
  3954. https://www.spoj.com/problems/MOZHSLS/ (5) //[VERY NICE]
  3955.  
  3956. http://www.spoj.com/problems/ADAFTBLL/ [Tree][Updates]
  3957.  
  3958. http://codeforces.com/gym/101879/problem/H (5) //[NICE][CLASSICAL][FREQUENCIES][FENWICK][BS]
  3959.  
  3960. http://www.spoj.com/problems/FREQUENT/
  3961.  
  3962. http://codeforces.com/contest/86/problem/D (4) //[NICE][CLASSICAL]
  3963.  
  3964. http://codeforces.com/contest/877/problem/F (6) //[NICE][NORMALIZE]
  3965.  
  3966. http://codeforces.com/problemset/problem/687/D
  3967.  
  3968. http://codeforces.com/problemset/problem/617/E
  3969.  
  3970. http://www.spoj.com/problems/DCEPCA09/
  3971.  
  3972. http://www.spoj.com/problems/COT2/
  3973.  
  3974. https://www.codechef.com/problems/DISTNUM3 //Tree + Update
  3975.  
  3976. https://toph.ws/p/distinct-dishting //Not sure if still working??
  3977.  
  3978. https://www.codechef.com/problems/CHEFNUMK
  3979.  
  3980. https://www.hackerearth.com/problem/algorithm/harry-gets-into-infy-1/description/
  3981.  
  3982. http://www.spoj.com/problems/COT/ (7) //ON TREE [but very tight TLE]
  3983.  
  3984. http://www.spoj.com/problems/GOT/ (5) //ON TREE
  3985.  
  3986. http://www.spoj.com/problems/CPAIR2/ (4) //MO + Fenwick [VERY NICE]
  3987.  
  3988. http://www.spoj.com/problems/HRSIAM/ (5) //With updates
  3989.  
  3990. http://www.spoj.com/problems/KDOMINO/ (4) //NICE &mdash; Frequencies
  3991.  
  3992. </spoiler>
  3993.  
  3994. <spoiler summary="next">
  3995.  
  3996. https://codeforces.com/contest/1187/problem/B (3) //[NICE]
  3997.  
  3998. 13257 - License Plates [UVA](3) //Brute-Force 26^3 queries in O(1)
  3999.  
  4000. http://codeforces.com/contest/92/problem/C (3) //[VERY NICE]
  4001.  
  4002. LightOJ 1157
  4003.  
  4004. https://www.codechef.com/problems/ASTRING
  4005.  
  4006. http://www.spoj.com/problems/MAIN8_E/
  4007.  
  4008. http://codeforces.com/problemset/problem/701/C
  4009.  
  4010. http://www.spoj.com/problems/STRSEQ/ //+DP
  4011.  
  4012. http://codeforces.com/problemset/problem/762/C
  4013.  
  4014. http://codeforces.com/problemset/problem/724/D
  4015.  
  4016. http://www.spoj.com/problems/SUBSN/ //+BS
  4017.  
  4018. https://www.hackerrank.com/contests/world-codesprint-5/challenges/short-palindrome //+DP
  4019.  
  4020. </spoiler>
  4021.  
  4022. <spoiler summary="np-hard">
  4023.  
  4024. http://www.spoj.com/problems/ADACROW
  4025.  
  4026. http://www.spoj.com/problems/ADAPARTY/
  4027.  
  4028. http://www.spoj.com/problems/ADAPARTI/
  4029.  
  4030. http://codeforces.com/gym/101908/problem/J (6) //[VERY NICE][STEINER][GEOMETRY]
  4031.  
  4032. http://codeforces.com/gym/101666 [G] (6) //[NICE][BURTE FORCE][OBSERVATION][SUBSETS]
  4033.  
  4034. http://codeforces.com/contest/907/problem/E (5) //[VERY NICE][CLIQUE][DP]
  4035.  
  4036. http://codeforces.com/contest/114/problem/B (3) //[CLIQUE][BRUTE-FORCE]
  4037.  
  4038. http://www.spoj.com/problems/JOHNNY/ //Not exact &mdash; points
  4039.  
  4040. http://www.spoj.com/problems/TAKIN/ (3) //[KNAPSACK][RECURSION]
  4041.  
  4042. http://codeforces.com/contest/839/problem/E (5) //NICE! Max-Clique
  4043.  
  4044. 7743 - Cliques (Similar to ADAPARTI) (8) //Parametrisation
  4045.  
  4046. 7616 Counting Cliques (4) //[NICE][CLIQUES][ELIMINATING-SETS]
  4047.  
  4048. </spoiler>
  4049.  
  4050. <spoiler summary="number_rectangle">
  4051.  
  4052. https://codeforces.com/contest/1181/problem/A (2) //[EASY][FORMULA][MODULO]
  4053.  
  4054. https://www.spoj.com/problems/PRADIPSUM/ (2) //[EASY][FORMULA]
  4055.  
  4056. UVA 10667 //Largest rectangle
  4057.  
  4058. UVA 10074 //Largest rectangle
  4059.  
  4060. UVA 836 //Largest rectangle
  4061.  
  4062. UVA 1330 //Largest rectangle
  4063.  
  4064. 12192 UVA 5
  4065.  
  4066. http://codeforces.com/contest/729/problem/B 2
  4067.  
  4068. http://codeforces.com/contest/710/problem/C 4
  4069.  
  4070. 11871 UVA 6
  4071.  
  4072. 11617 UVA (3)
  4073.  
  4074. 11573 UVA (4)
  4075.  
  4076. 11499 UVA (5)
  4077.  
  4078. 11230 UVA (4)
  4079.  
  4080. http://www.spoj.com/problems/JOCHEF/ (5) //NICE: Lagers rectange 0/1 O(N*M)
  4081.  
  4082. </spoiler>
  4083.  
  4084. <spoiler summary="number_theory">
  4085.  
  4086. http://www.spoj.com/problems/ADAGCD/ [+STL]
  4087.  
  4088. http://www.spoj.com/problems/ADAHACK/
  4089.  
  4090. http://www.spoj.com/problems/ADADUNG/
  4091.  
  4092. http://www.spoj.com/problems/ADACAROT/
  4093.  
  4094. http://www.spoj.com/problems/ADACON/
  4095.  
  4096. http://www.spoj.com/problems/ADATAXES/
  4097.  
  4098. http://www.spoj.com/problems/ADADIG/
  4099.  
  4100. http://www.spoj.com/problems/ADASETS/
  4101.  
  4102. https://codeforces.com/gym/102302/problem/G (8) //[OBSERVE][EASY IMPLE]
  4103.  
  4104. https://codeforces.com/contest/1206/problem/B (2) //[IMPLE][IF]
  4105.  
  4106. https://codeforces.com/contest/1177/problem/B (4) //[NICE][LOGARITHM]
  4107.  
  4108. https://codeforces.com/contest/1148/problem/G (6) //[VERY NICE][RANDOM][FACTORISATION][GCD][PRIME]
  4109.  
  4110. https://codeforces.com/contest/1175/problem/A (2) //[EASY][SYMPATHIC][DIVISION]
  4111.  
  4112. https://codeforces.com/contest/1203/problem/C (3) //[NICE][GCD]
  4113.  
  4114. https://devskill.com/CodingProblems/ViewProblem/553 (3) //[VERY NICE][SIMPLE]
  4115.  
  4116. https://devskill.com/CodingProblems/ViewProblem/560 (2)
  4117.  
  4118. https://codeforces.com/contest/1176/problem/B (2) //[MODULO][GREEDY]
  4119.  
  4120. https://codeforces.com/contest/1200/problem/C (4) //[VERY NICE][GCD][LCM]
  4121.  
  4122. https://codeforces.com/contest/1182/problem/A (2) //[EASY][DP]
  4123.  
  4124. https://atcoder.jp/contests/abc136/tasks/abc136_b (2) //[IMPLEMENTATION][CONVERSION]
  4125.  
  4126. https://codeforces.com/contest/1185/problem/A (1)
  4127.  
  4128. https://codeforces.com/contest/1198/problem/F (6) //[VERY NICE][RANDOM][FACTORISATION][PRIME][GCD]
  4129.  
  4130. https://codeforces.com/contest/1183/problem/B (2) //[EASY][FORMULA][MIN/MAX]
  4131.  
  4132. https://codeforces.com/contest/1187/problem/A (1) //[EASY][FORMULA]
  4133.  
  4134. https://codeforces.com/contest/1195/problem/B (2) //[EASY][GAUSS][BRUTE]
  4135.  
  4136. https://codeforces.com/contest/1189/problem/E (5) //[INVERSION][STL]
  4137.  
  4138. https://www.spoj.com/problems/CANPR/ (5) //[NICE][MOBIUS] Weird TC (weak?)
  4139.  
  4140. https://www.spoj.com/problems/OVISLARSUM/ (3) //[FORMULA][128]
  4141.  
  4142. https://www.urionlinejudge.com.br/judge/en/problems/view/2876 (6) //[VERY NICE][GCD][IE]
  4143.  
  4144. https://codeforces.com/gym/102058/problem/E (3) //[BRUTE-FORCE][GCD]
  4145.  
  4146. https://codeforces.com/gym/101972/problem/A (3) //[EASY][SIMULATION]
  4147.  
  4148. https://toph.co/p/pascals-triangle (2)
  4149.  
  4150. https://toph.co/p/big-factorials (1)
  4151.  
  4152. https://www.codechef.com/viewsolution/21428053 (4) //[SORTING][ANGLES][MATH][COSINUS]
  4153.  
  4154. http://codeforces.com/gym/101962 [C] (4)
  4155.  
  4156. http://codeforces.com/gym/101808/problem/G (4) //[GCD][IF][LCM]
  4157.  
  4158. http://codeforces.com/gym/101666 [L] (5) //[GREED][DP] Logarithms
  4159.  
  4160. http://codeforces.com/gym/101666 [C] (4) //[NICE][GCD]
  4161.  
  4162. 13287 - Shattered Cake (2) //Rectangle
  4163.  
  4164. http://codeforces.com/gym/101650 [G](3) //Graphs
  4165.  
  4166. http://codeforces.com/contest/934/problem/D (4) //Polynomials
  4167.  
  4168. 8253 - Boss Battle [LA] (2)
  4169.  
  4170. http://codeforces.com/contest/919/problem/E (5) //[MODULAR-MATH]
  4171.  
  4172. http://codeforces.com/contest/149/problem/B (3) //Base to 10
  4173.  
  4174. http://codeforces.com/contest/148/problem/B (3) //[SIMULATION](math or bs)
  4175.  
  4176. http://codeforces.com/contest/148/problem/A (2) //[EASY][SIEVE][BRUTE-FOCE][LCM][IE]
  4177.  
  4178. http://www.spoj.com/problems/JGTLE/ (3) //Sum reduction
  4179.  
  4180. http://www.spoj.com/problems/BAPM/ (3) //Simple power / Observe, rare colisions
  4181.  
  4182. http://codeforces.com/contest/911/problem/C (2) //[Observation][Iff (or brute-froce)]
  4183.  
  4184. http://codeforces.com/contest/133/problem/B (2) //Bases + implementation
  4185.  
  4186. http://codeforces.com/contest/129/problem/A (1) //Parity
  4187.  
  4188. http://codeforces.com/contest/124/problem/D (4)
  4189.  
  4190. http://codeforces.com/contest/125/problem/A (1) //mod/div simple - if
  4191.  
  4192. http://codeforces.com/contest/902/problem/D (4) //Polynomials / Fibonacci / Bitset
  4193.  
  4194. http://codeforces.com/contest/899/problem/D (4) //X99999 possibilities
  4195.  
  4196. http://codeforces.com/contest/899/problem/C (3) //[NICE][GREEDY KNAPSACK]
  4197.  
  4198. http://codeforces.com/contest/899/problem/A (1)
  4199.  
  4200. http://codeforces.com/contest/898/problem/A (1)
  4201.  
  4202. http://codeforces.com/gym/101620 {F}(4) //[IFS][INVERSE][CASES]
  4203.  
  4204. http://codeforces.com/contest/900/problem/D (4) //[NICE][DIVISORS][GCD][IE]
  4205.  
  4206. http://codeforces.com/contest/900/problem/B (2) //Cycles or Brute-force + Division
  4207.  
  4208. http://codeforces.com/contest/119/problem/A (2) //[EASY][GCD]
  4209.  
  4210. 8014 - Birthday Pizza Party (4) //[NICE][OVERFLOW][LCM WITH SHIFT]
  4211.  
  4212. 7629 - Powers (3) //One path is factorisation
  4213.  
  4214. 8037 - Military Service (2) //Sample formula
  4215.  
  4216. 8085 - Divisors (4) //[NICE][PRIMES/FACTORISATION/SIEVE]
  4217.  
  4218. 6589 - Captain Obvious and the Rabbit-Man (7) //Sylvester's formula
  4219.  
  4220. 6582 - Magical GCD (4) //[NICE] - Data structures works too
  4221.  
  4222. 8000 - FizzBuzz (1)
  4223.  
  4224. https://devskill.com/CodingProblems/ViewProblem/421 (2) //6 buckets
  4225.  
  4226. http://codeforces.com/contest/93/problem/E (5) //[VERY NICE][DP][RECURSION]
  4227.  
  4228. http://codeforces.com/contest/86/problem/A (3) //[NICE] 50* is best (unless more digits)
  4229.  
  4230. http://codeforces.com/contest/83/problem/D (5) //[VERY NICE][PRIMES][BRUTE-FORE-2]
  4231.  
  4232. http://codeforces.com/contest/82/problem/A (2) //Simulation
  4233.  
  4234. http://codeforces.com/contest/74/problem/C (4) //gcd
  4235.  
  4236. http://codeforces.com/contest/76/problem/E (4) //Divide sumations [BF]
  4237.  
  4238. http://codeforces.com/contest/71/problem/C (3) //[EASY][NICE][BRUTE-FORCE][DIVISORS]
  4239.  
  4240. http://codeforces.com/contest/70/problem/A (2) //3^(N-1)
  4241.  
  4242. http://codeforces.com/contest/43/problem/C (2) //Moduly by 3 {0/2+min(1,2)}
  4243.  
  4244. http://codeforces.com/contest/50/problem/A (1) //[EASY]
  4245.  
  4246. http://codeforces.com/contest/61/problem/C (4) //Base conversion + roman
  4247.  
  4248. UVA 355 //bases conversion
  4249.  
  4250. 2559 [LA] //Base conversion
  4251.  
  4252. https://www.codechef.com/problems/COPRIME3 //Cyka Möbius
  4253.  
  4254. http://www.spoj.com/problems/PSTR/ //Cyka Möbius
  4255.  
  4256. http://codeforces.com/problemset/problem/803/F //Cyka Möbius
  4257.  
  4258. https://devskill.com/CodingProblems/ViewProblem/23
  4259.  
  4260. http://codeforces.com/contest/731/problem/F 4
  4261.  
  4262. 12031 UVA (8)
  4263.  
  4264. http://codeforces.com/contest/722/problem/F (8)
  4265.  
  4266. http://codeforces.com/contest/716/problem/C 4
  4267.  
  4268. http://codeforces.com/contest/711/problem/E (8)
  4269.  
  4270. http://codeforces.com/contest/710/problem/D (6)
  4271.  
  4272. 13154 (UVA) 7
  4273.  
  4274. 13166 (UVA) 5
  4275.  
  4276. 11962 (UVA) 2
  4277.  
  4278. 11718 UVA 3
  4279.  
  4280. 11510 UVA (5)
  4281.  
  4282. 11538 UVA (3) //good one &mdash; just math
  4283.  
  4284. 11556 UVA (1)
  4285.  
  4286. http://codeforces.com/contest/757/problem/E (8)
  4287.  
  4288. http://codeforces.com/contest/758/problem/F (7)
  4289.  
  4290. 11481 UVA (4)
  4291.  
  4292. 11237 UVA (4) //Nice &mdash; seems like knapsbag but it it not
  4293.  
  4294. 11155 UVA (4) //Almost as previous problem
  4295.  
  4296. 11038 UVA (3) //counting digits on interval
  4297.  
  4298. http://codeforces.com/contest/763/problem/C (7)
  4299.  
  4300. 11087 UVA (4) //Sums of two numbers divisible with <=500 (10^5)
  4301.  
  4302. http://codeforces.com/contest/678/problem/C 2 //LCM
  4303.  
  4304. http://codeforces.com/problemset/problem/665/F (8) //p^3 | p*q
  4305.  
  4306. http://www.spoj.com/problems/LCMSUM/ //Vzorec v knihovničce
  4307.  
  4308. http://www.spoj.com/problems/FRNDZND/ (2) // (size 1 == 1, else 0)
  4309.  
  4310. http://www.spoj.com/problems/EXPOR/ //bit-by-bit (+ formula)
  4311.  
  4312. http://www.spoj.com/problems/FACTDIV/ (5) //dyn-update of ans/factors GOOD
  4313.  
  4314. http://www.spoj.com/problems/PAIRDIV/ (6) //cyka möbius -_-
  4315.  
  4316. http://www.spoj.com/problems/FCDC/ (4) //keep factorized factorial
  4317.  
  4318. http://www.spoj.com/problems/NTHPRIME/ (7) // BS + NumPrime GOOD!!
  4319.  
  4320. http://www.spoj.com/problems/DIVFACT3/ (7) // Sieve 10^8 + sqrt search
  4321.  
  4322. http://www.spoj.com/problems/DIVFACT4/ (8) // Prime count
  4323.  
  4324. http://codeforces.com/contest/776/problem/C (4) //segments div. by number
  4325.  
  4326. http://codeforces.com/contest/776/problem/E (6) //vypsat cisla: f(N)=Phi(N),g(N)=N
  4327.  
  4328. http://www.spoj.com/problems/PHT/ (2) //easy BS (NN+2N) mby math?
  4329.  
  4330. http://www.spoj.com/problems/GCDEX/ (7) //OEIS A006579 &mdash; enough [well imp]
  4331.  
  4332. http://www.spoj.com/problems/APS/ (3) //just sieve + generate
  4333.  
  4334. http://www.spoj.com/problems/WPC5I/ (3)//fc: C[a]!=C[b]:F[a]^max(C[a],C[b])
  4335.  
  4336. http://www.spoj.com/problems/SPEC_SET/ N→N/k→N/k/k
  4337.  
  4338. http://www.spoj.com/problems/DCEPC11B/ (5) //Wilson't theorem!
  4339.  
  4340. http://www.spoj.com/problems/FACTMULN/ (5) //each f[i]/c[i] separately
  4341.  
  4342. http://www.spoj.com/problems/SPCM/ (4) //just factorisation + prime check (10^12)
  4343.  
  4344. http://www.spoj.com/problems/TWOGAME/ (5) //gcd == Power of 3 => YES
  4345.  
  4346. http://www.spoj.com/problems/MKEQUAL/ (2) //Chceck if sum is divisible by N
  4347.  
  4348. http://www.spoj.com/problems/TIPTOP/ (3) //sqrt(N)==N? NICE!!
  4349.  
  4350. http://www.spoj.com/problems/PSYCHON/ (4) // fast factorisation
  4351.  
  4352. http://www.spoj.com/problems/ENIGMATH/ (1) // swap and div by gcd
  4353.  
  4354. http://www.spoj.com/problems/SNGPG/ (3) // prime gen + check
  4355.  
  4356. http://codeforces.com/contest/795/problem/A (2) //brute-force
  4357.  
  4358. http://codeforces.com/contest/801/problem/E (6) //NICE! &mdash; Clique-DAG + inversion
  4359.  
  4360. http://codeforces.com/contest/798/problem/C (4) //GCD == at the beginning OR 2
  4361.  
  4362. http://codeforces.com/contest/803/problem/C (3) //Only "low" K and just divisors
  4363.  
  4364. 10830 (4) //simple add 2→ sqrt(N) + their mirrors
  4365.  
  4366. http://codeforces.com/contest/817/problem/A (2) //check division + parity
  4367.  
  4368. 13209 UVA (3) //Simple simulation of division (+states rememberance)
  4369.  
  4370. http://codeforces.com/contest/834/problem/C (4) //Has cube-root + both num divisible by cuberoot
  4371.  
  4372. http://codeforces.com/contest/837/problem/E (5) //Factorisation + GCD attributes
  4373.  
  4374. http://www.spoj.com/problems/SUMMATION/ (3) //Number contribution: 2^(N-1)
  4375.  
  4376. http://www.spoj.com/problems/SECTORS/ (4) //Odd len OR sum of odd indices == sum of even
  4377.  
  4378. http://www.spoj.com/problems/IITKWPCM/ (6) //VERY NICE &mdash; Gauss's generalisation of Wilsons Theorem
  4379.  
  4380. http://www.spoj.com/problems/UCV2013A/ (4) //N*(N^L-1)/(N-1)
  4381.  
  4382. http://www.spoj.com/problems/KIMO1/ (4) //NICE &mdash; Adding/Subing by modulus
  4383.  
  4384. http://www.spoj.com/problems/AFS2/ (4) //Sum of divisort (sqrt(N)) &mdash; (+128int)
  4385.  
  4386. http://www.spoj.com/problems/FUNNUMS/ (4) //Permutations (get ith + guess ith)
  4387.  
  4388. http://www.spoj.com/problems/MAY99_3/ (3) //GCD
  4389.  
  4390. http://www.spoj.com/problems/PUCMM334/ (3) //Classical hats problem
  4391.  
  4392. http://www.spoj.com/problems/LCPC11B/ (4) //Factorize + count all subsets
  4393.  
  4394. http://www.spoj.com/problems/THREENUMBERS/ (2) //EASY & NICE [lcm]
  4395.  
  4396. http://www.spoj.com/problems/GAMES/ (2) //EASY&NICE &mdash; Go discrete (by 10^k) → 10^k/GCD
  4397.  
  4398. http://www.spoj.com/problems/SUBSHARD/ (4) //dig*10^sufix*(choose sufix)*^Prefix [VERY NICE]
  4399.  
  4400. http://www.spoj.com/problems/INVDIV/ (6) //Sum of divisors function + factorisation [NICE]
  4401.  
  4402. http://www.spoj.com/problems/JNEXT/ (2) //EASY &mdash; Zahřívačka pro prváky
  4403.  
  4404. http://www.spoj.com/problems/TSHOW1/ (3) //NICE &mdash; Almost as binary repre with 5/6
  4405.  
  4406. http://codeforces.com/contest/859/problem/B (2) //Easy by iteration
  4407.  
  4408. http://codeforces.com/contest/861/problem/A (2) //5,2 division [EASY]
  4409.  
  4410. http://www.spoj.com/problems/ABA12D/ (4) //NICE &mdash; Formula for sum divisors Prod(Sum(fac-powers))
  4411.  
  4412. http://www.spoj.com/problems/MAIN74/ (3) //Fibo's
  4413.  
  4414. http://www.spoj.com/problems/NOSQ/ (3) //Sieve + Digit check
  4415.  
  4416. http://www.spoj.com/problems/SQUAREV1/ (3) //NICE (but dumb code limit)
  4417.  
  4418. http://codeforces.com/contest/597/problem/A (1) //Simple if+2*Divide
  4419.  
  4420. http://www.spoj.com/problems/STREETR/ (3) //Easy [GCD]
  4421.  
  4422. http://www.spoj.com/problems/HPYNOSII/ (3) //<=1000 after first move
  4423.  
  4424. http://www.spoj.com/problems/HPYNOS/ (1) //Same as above &mdash; 1 number
  4425.  
  4426. http://www.spoj.com/problems/IITD4/ (3) //Brute-force [sieve-like]
  4427.  
  4428. http://www.spoj.com/problems/GIRLSNBS/ (2) //Some easy formula
  4429.  
  4430. http://www.spoj.com/problems/GUESSTHE/ (2) //NICE [EASY][LCM]
  4431.  
  4432. http://codeforces.com/contest/867/problem/B (2) //NICE [observation][1 2]
  4433.  
  4434. http://www.spoj.com/problems/NDIVPHI/ (4) //NICE &mdash; Multiple of lowest primes [BIG-INT]
  4435.  
  4436. http://www.spoj.com/problems/NDIVPHI2/ (5) //NICE &mdash; Same as above [bigger constraints]
  4437.  
  4438. http://codeforces.com/contest/6/problem/A (1) //Triangle check (4 pts)
  4439.  
  4440. http://codeforces.com/contest/869/problem/B (1) //Answer is usually 0
  4441.  
  4442. http://codeforces.com/contest/9/problem/C (2) //Bases (2→ 10)
  4443.  
  4444. http://codeforces.com/contest/20/problem/B (2) //Ax^2+Bx+C=0 (find roots)
  4445.  
  4446. http://codeforces.com/contest/27/problem/E (5) //[VERY NICE]: Factorisation+Recursion
  4447.  
  4448. http://codeforces.com/contest/32/problem/C (3) //DSU works too
  4449.  
  4450. http://codeforces.com/contest/872/problem/C (3) //NICE &mdash; Compose of 4 (mby one 6 or 9)
  4451.  
  4452. http://codeforces.com/contest/876/problem/B (3) //Group by modulo
  4453.  
  4454. </spoiler>
  4455.  
  4456. <spoiler summary="observation">
  4457.  
  4458. http://www.spoj.com/problems/ADABANKET/ //Observation (but Stoer-Wagner works too)
  4459.  
  4460. https://codeforces.com/gym/102302/problem/C (5) //[NICE][STL][BF]
  4461.  
  4462. https://codeforces.com/gym/102307/problem/K (4) //[NICE][FIBO][NUMBER THEORY]
  4463.  
  4464. https://codeforces.com/contest/1206/problem/D (5) //[VERY NICE][PARAMETRISATION][REDUCTION][BFS]
  4465.  
  4466. https://codeforces.com/contest/1204/problem/D1 (4) //[or DP][FIXED][GREEDY][STACK]
  4467.  
  4468. https://codeforces.com/contest/1204/problem/D2 (5) // ^^^
  4469.  
  4470. https://codeforces.com/contest/1194/problem/A (1) //[TRIVIAL]
  4471.  
  4472. https://www.spoj.com/problems/ARRTWIST/ (3)
  4473.  
  4474. https://www.spoj.com/problems/OPMODULO/ (3) //[NICE]Brute-force and observe
  4475.  
  4476. https://codeforces.com/gym/102001/problem/I (2) //[PARITY]
  4477.  
  4478. https://codeforces.com/gym/102001/problem/A (4) //[VERY NICE][FREQUENCY]
  4479.  
  4480. https://codeforces.com/gym/101991/problem/L (3) //[NICE][EASY][BITS]
  4481.  
  4482. https://codeforces.com/gym/102021 [F] (3) //[NICE][SEQENCE]
  4483.  
  4484. https://www.codechef.com/problems/BUDDYNIM (3) //[OBSERVATION][NICE]
  4485.  
  4486. http://codeforces.com/gym/101962/problem/H (4) //[SEQUENCES][SIMULATION]
  4487.  
  4488. http://codeforces.com/contest/922/problem/C (3) //Note that K is always very low
  4489.  
  4490. http://codeforces.com/contest/912/problem/B (2) //Bits/XOR
  4491.  
  4492. http://codeforces.com/contest/911/problem/D (3) //[VERY NICE]
  4493.  
  4494. http://codeforces.com/contest/902/problem/E (5) //[VERY NICE] //LCT works too
  4495.  
  4496. 7589 Rearranging a Sequence (3) //Print from back and then real
  4497.  
  4498. http://codeforces.com/gym/101630 {A}(6) //[NICE][STL]
  4499.  
  4500. http://codeforces.com/contest/122/problem/B (1) //just 4 or 7
  4501.  
  4502. http://codeforces.com/contest/116/problem/E (6) //[NICE][COMBINATORICS][FIND ANY]
  4503.  
  4504. http://codeforces.com/contest/892/problem/D (4) //NICE [SORTING]
  4505.  
  4506. http://codeforces.com/contest/897/problem/E (5) //[NICE][SET] //2 will beat all
  4507.  
  4508. 7730 To begin or not to begin (3) //Parity
  4509.  
  4510. http://codeforces.com/contest/122/problem/D (4) //[NICE] Sweep /OR/ cycle
  4511.  
  4512. http://codeforces.com/contest/128/problem/D (6) //Normalize + Sweeps
  4513.  
  4514. </spoiler>
  4515.  
  4516. <spoiler summary="oeis">
  4517.  
  4518. https://codeforces.com/gym/101981 [G] (3) //A000332
  4519.  
  4520. https://codeforces.com/gym/102001/problem/C //De Bruine
  4521.  
  4522. 6591 - Bus (2) //2^N-1
  4523.  
  4524. 12004 UVA 2
  4525.  
  4526. 11273 UVA 5 //https://oeis.org/A001088
  4527.  
  4528. 11077 UVA 3 //https://oeis.org/A094638
  4529.  
  4530. http://www.spoj.com/problems/VECTAR5/ 3 //https://oeis.org/A038721
  4531.  
  4532. http://www.spoj.com/problems/ESYRCRTN/ 2 //generate and see
  4533.  
  4534. http://www.spoj.com/problems/IITWPC4B/ 3 //http://oeis.org/A005044
  4535.  
  4536. http://www.spoj.com/problems/POLCONST/ (4) //A003401+Fermat Number (Prime)
  4537.  
  4538. http://www.spoj.com/problems/CUTCAKE/ (3) // pattern [1 22 333 4444 55555]
  4539.  
  4540. 10872 UVA 3 //Alcuin's Sequence
  4541.  
  4542. http://www.spoj.com/problems/LOVINGPW/ (3) //A000788
  4543.  
  4544. http://www.spoj.com/problems/CBANK/ (3) //A000292 Tetrahedral numbers
  4545.  
  4546. http://www.spoj.com/problems/GUMATH2/ (4) //A000240 Modulo by MOD*2
  4547.  
  4548. http://www.spoj.com/problems/MATHII/ (4) //A006218 (Two formulas => sqrt(N))
  4549.  
  4550. http://www.spoj.com/problems/KOPC12B/ (4) //A002457 (factorial + factorial modular)
  4551.  
  4552. http://www.spoj.com/problems/YUMMY/ (4) //A006534
  4553.  
  4554. http://www.spoj.com/problems/ADV04B1/ (5) //A001850
  4555.  
  4556. http://www.spoj.com/problems/FLWRS/ (4) //A002464
  4557.  
  4558. http://www.spoj.com/problems/RANJAN02/ (3) //A024023
  4559.  
  4560. http://www.spoj.com/problems/BOMARBLE/ (2) //A000326
  4561.  
  4562. http://codeforces.com/contest/57/problem/C (4) //A045992
  4563.  
  4564. http://codeforces.com/contest/918/problem/A (1) //Fibo
  4565.  
  4566. </spoiler>
  4567.  
  4568. <spoiler summary="offline">
  4569.  
  4570. http://www.spoj.com/problems/ADARAIN/
  4571.  
  4572. http://www.spoj.com/problems/ADARAINB/
  4573.  
  4574. http://www.spoj.com/problems/ADAROBOT/
  4575.  
  4576. https://codeforces.com/gym/102307/problem/D (4) //[NICE][PREPROCESS][SQRT][DSU]
  4577.  
  4578. https://www.spoj.com/problems/CLFLARR/ (3) //[NICE][EASY][QUEUE][STL]
  4579.  
  4580. https://codeforces.com/gym/102021 [M] (5) //[VERY NICE][SPANNING]//LCA WORKS TOO
  4581.  
  4582. http://codeforces.com/gym/101840 [I] (4) //[NICE][PREPROCESS]
  4583.  
  4584. http://codeforces.com/problemset/problem/816/B //Easier ST
  4585.  
  4586. 11266 UVA (6) //slightly knapsack || [NICE]
  4587.  
  4588. http://codeforces.com/contest/761/problem/F (7)
  4589.  
  4590. http://www.spoj.com/problems/UPDATEIT/ (2) //basic method
  4591.  
  4592. 13189 UVA (4) //simulation + sort queries
  4593.  
  4594. http://www.spoj.com/problems/HAYBALE/ (3) //Basic sum + sort (segment tree would work too)
  4595.  
  4596. http://codeforces.com/gym/101597/problem/H (6) //Offline 2D sum + geometry
  4597.  
  4598. </spoiler>
  4599.  
  4600. <spoiler summary="palindromes">
  4601.  
  4602. https://codeforces.com/gym/102307/problem/B (3) //[BF][SUFFIX]
  4603.  
  4604. https://www.spoj.com/problems/JUSTAPAL/ (6) //[VERY NICE][SA][RMQ]
  4605.  
  4606. https://www.spoj.com/problems/DRAGKING/ (4) //[CLASSICAL][DP]
  4607.  
  4608. https://codeforces.com/gym/101981 (5) //[NICE][SEGMENT][MANACHER][ZETA][SA]
  4609.  
  4610. https://codeforces.com/gym/101972/problem/F (3) //[EASY][OBSERVATION][GREEDY]
  4611.  
  4612. http://codeforces.com/gym/101628/problem/E (4) //[NICE][DP] //Easy
  4613.  
  4614. http://codeforces.com/gym/101864 [J] (5) //[NICE][MANACHER]
  4615.  
  4616. http://codeforces.com/gym/101806/problem/Q (4) //[HASHING][PALINDROMIC-TREE]
  4617.  
  4618. http://codeforces.com/contest/897/problem/B (2) //Palindromic numbers [EASY][FIRST]
  4619.  
  4620. http://codeforces.com/contest/883/problem/H (3) //Make as least odd as possible
  4621.  
  4622. http://code-festival-2017-qualc.contest.atcoder.jp/tasks/code_festival_2017_qualc_c (3) //Similar to remove-dp, but greedy
  4623.  
  4624. http://code-festival-2017-qualc.contest.atcoder.jp/tasks/code_festival_2017_qualc_d (4) //DP with greedy thinking
  4625.  
  4626. http://codeforces.com/contest/59/problem/C (3) //Implementation [constructive]
  4627.  
  4628. UVA 13092 //manacher
  4629.  
  4630. http://www.spoj.com/problems/MSUBSTR/ //manacher
  4631.  
  4632. UVA 11888 //manacher
  4633.  
  4634. https://www.hackerrank.com/contests/101hack35/challenges/circular-palindromes //manacher
  4635.  
  4636. UVA 12378 //manacher
  4637.  
  4638. https://www.hackerrank.com/contests/world-codesprint-5/challenges/challenging-palindromes //SA
  4639.  
  4640. http://www.spoj.com/problems/NUMOFPAL/ //Palindromic Tree
  4641.  
  4642. http://codeforces.com/problemset/problem/245/H //# of palindromes [DP]
  4643.  
  4644. http://www.spoj.com/problems/ANAGR/ 2 //frequency + palindromes
  4645.  
  4646. http://www.spoj.com/problems/AMR12D/ (1) //Palindrome check //Zahrivacka pro prvaky
  4647.  
  4648. http://codeforces.com/problemset/problem/835/D //Hashing
  4649.  
  4650. http://codeforces.com/contest/137/problem/D (4) //[NICE][DP]
  4651.  
  4652. </spoiler>
  4653.  
  4654. <spoiler summary="patter-matching">
  4655.  
  4656. 11019 UVA (5)
  4657.  
  4658. </spoiler>
  4659.  
  4660. <spoiler summary="permutations">
  4661.  
  4662. http://codeforces.com/contest/137/problem/B (1) //Frequency + size
  4663.  
  4664. http://codeforces.com/contest/136/problem/A (1) //Permutation cycles
  4665.  
  4666. http://codeforces.com/contest/844/problem/C 3 //NICE Permutations in array
  4667.  
  4668. http://codeforces.com/contest/48/problem/D (3) //NICE [frequency array]
  4669.  
  4670. http://codeforces.com/contest/56/problem/B (2) //Restore from 1 reverse [EASY]
  4671.  
  4672. http://codeforces.com/contest/122/problem/D (5) //NICE [BRUTE-FORCE]//ONLY BACK MATTERS
  4673.  
  4674. </spoiler>
  4675.  
  4676. <spoiler summary="persistent_segment_tree">
  4677.  
  4678. http://codeforces.com/contest/893/problem/F (6) //[VERY NICE][EULER TOUR]
  4679.  
  4680. http://codeforces.com/contest/813/problem/E (6) //Easy but hard data structure
  4681.  
  4682. https://codeforces.com/contest/893/problem/F //Suggested by [user:phibrain]
  4683.  
  4684. </spoiler>
  4685.  
  4686. <spoiler summary="preprocess">
  4687.  
  4688. http://www.spoj.com/problems/ADAPLUS/
  4689.  
  4690. https://codeforces.com/contest/1169/problem/E (5) //[VERY NICE][DP][NEXT][BITS]
  4691.  
  4692. https://codeforces.com/contest/1175/problem/E (5) //[VERY NICE][LIFTING][PRIORITY]
  4693.  
  4694. https://codeforces.com/contest/1181/problem/C (4) //[VERY NICE][RMQ]
  4695.  
  4696. https://atcoder.jp/contests/abc136/tasks/abc136_d (4) //[NICE][PARITY]
  4697.  
  4698. https://codeforces.com/contest/1194/problem/B (3) //[IMPLEMENTATION][INDEXING]
  4699.  
  4700. http://www.spoj.com/problems/ADASQR/ [Monotone Queue]
  4701.  
  4702. https://toph.co/p/rio-and-inversion (5) //[NICE][INVERSIONS][PREFIX SUM][2D]
  4703.  
  4704. http://codeforces.com/gym/101801 [I] (3) //[PREFIX SUM]
  4705.  
  4706. http://codeforces.com/gym/101889 [L] (5) //[NICE][PREFIX SUM][BINARY SEARCH]
  4707.  
  4708. http://codeforces.com/contest/120/problem/D (3) //But maybe work naively ?!
  4709.  
  4710. http://codeforces.com/contest/48/problem/B (2) //2D Prefix Sum [BF prolly works too]
  4711.  
  4712. http://codeforces.com/problemset/problem/761/F
  4713.  
  4714. VA 10360 //2D Prefix Sum
  4715.  
  4716. UVA 983 //2D Prefix Sum
  4717.  
  4718. http://codeforces.com/contest/777/problem/C (4) //NICE
  4719.  
  4720. http://codeforces.com/contest/818/problem/C (4) //Prefix Sum
  4721.  
  4722. http://codeforces.com/contest/834/problem/B (2) //26 queries &mdash; NICE rozehrivacka pro prvaky
  4723.  
  4724. http://www.spoj.com/problems/RANGESUM/ (4) //NICE: Offline (delta) + Prefix Sum
  4725.  
  4726. http://www.spoj.com/problems/RANDG/ (3) //NICE [but too low bounds] [PrefixSum] [Try all indexes]
  4727.  
  4728. http://www.spoj.com/problems/HARSHAD/ (3) //Sieve + simple function
  4729.  
  4730. http://www.spoj.com/problems/PUCMM210/ (3) //Number theory (thinking not necessary)
  4731.  
  4732. http://www.spoj.com/problems/BCAKE/ (3) //Prefix sum of rectangle + N^4
  4733.  
  4734. http://www.spoj.com/problems/PAIRSUM/ (4) //VERY NICE &mdash; Prefix sum + Prefix PW sum
  4735.  
  4736. http://www.spoj.com/problems/MAIN111/ (3) //Sieve + Brute Force (answer in O(1))
  4737.  
  4738. http://www.spoj.com/problems/PLUSEVI/ (4) //NICE &mdash; There are not many of them
  4739.  
  4740. http://codeforces.com/contest/18/problem/C (2) //Prefix sum End==2*i
  4741.  
  4742. http://codeforces.com/contest/873/problem/B (2) //Search for same prefix (+/-1)
  4743.  
  4744. http://codeforces.com/contest/33/problem/C (4) //Prefix sum + Sweep from back + sweep from front
  4745.  
  4746. http://codeforces.com/contest/872/problem/B (3) //Sweep from both sides (RMQ works too)
  4747.  
  4748. </spoiler>
  4749.  
  4750. <spoiler summary="prime-count">
  4751.  
  4752. http://www.spoj.com/problems/NTHPRIME/
  4753.  
  4754. http://www.spoj.com/problems/DIVFACT4/
  4755.  
  4756. http://codeforces.com/problemset/problem/665/F
  4757.  
  4758. https://www.codechef.com/problems/CNTPRIME
  4759.  
  4760. http://www.spoj.com/problems/SUMPRIM1/
  4761.  
  4762. http://www.spoj.com/problems/SUMPRIM2/ [NO &mdash; hard]
  4763.  
  4764. https://www.hackerrank.com/contests/projecteuler/challenges/euler010/problem //easy
  4765.  
  4766. </spoiler>
  4767.  
  4768. <spoiler summary="prime-testing">
  4769.  
  4770. http://www.spoj.com/problems/ADAGIFT/
  4771.  
  4772. https://codeforces.com/gym/102302/problem/J (5) //[NICE][NUMBER THEORY][SORTING]
  4773.  
  4774. https://www.spoj.com/problems/PRMFN/ (5) //[VERY NICE][GREEDY]
  4775.  
  4776. http://www.spoj.com/problems/PON/en/
  4777.  
  4778. http://www.spoj.com/problems/DAYOUT2C/en/ [EASY]
  4779.  
  4780. Project Euler #60: Prime pair sets
  4781.  
  4782. Project Euler #58: Spiral primes
  4783.  
  4784. Project Euler #131: Prime cube partnership
  4785.  
  4786. https://devskill.com/CodingProblems/ViewProblem/229
  4787.  
  4788. https://devskill.com/CodingProblems/ViewProblem/327
  4789.  
  4790. Gym 100753K [2015 German Collegiate Programming Contest (GCPC 15) + POI 10-T3]
  4791.  
  4792. Project Euler #130: Composites with prime repunit property
  4793.  
  4794. http://www.spoj.com/problems/ABA12A/ (3)
  4795.  
  4796. 10871 UVA (3) //Easy &mdash; fermat not necessary
  4797.  
  4798. http://www.spoj.com/problems/POP1/ (4) //Fast primality testing (or somehow)
  4799.  
  4800. http://www.spoj.com/problems/POP2/ (5) //NICE &mdash; same as above (yet with ll)
  4801.  
  4802. http://www.spoj.com/problems/POP3/ (6) //same as above (yet with big)
  4803.  
  4804. http://www.spoj.com/problems/DCEPC203/ (6) //NICE [optimalisation]
  4805.  
  4806. http://www.spoj.com/problems/PRIMPERM/ (4) //NICE (next_perm + sieve)
  4807.  
  4808. </spoiler>
  4809.  
  4810. <spoiler summary="probability">
  4811.  
  4812. https://codeforces.com/gym/102302/problem/F (4) //[PATTERN]
  4813.  
  4814. https://codeforces.com/contest/1173/problem/E1 (5) //[NICE][DP]
  4815.  
  4816. https://codeforces.com/contest/1194/problem/F (6) //[NICE][COMBINATORICS][PREPROCESS]
  4817.  
  4818. http://codeforces.com/gym/101982 (5) [K] (5) //[NICE][DP]
  4819.  
  4820. http://codeforces.com/gym/101845/problem/G (4) //[DP] Classical
  4821.  
  4822. http://codeforces.com/gym/101845/problem/M (3) //[NICE][OBSERVATION]
  4823.  
  4824. http://codeforces.com/gym/101726/problem/B (4) //[NICE][DP][BRUTE-FORCE]
  4825.  
  4826. https://www.devskill.com/CodingProblems/ViewProblem/470 (3) //Brute Force
  4827.  
  4828. 8262 - Knockout Tournament (4) [LA] //[NICE][SIMULATION] //Might not be working on LA (but on CF y)
  4829.  
  4830. http://codeforces.com/contest/912/problem/D (4) //[VERY NICE][EXPECT][DIJKSTRA]
  4831.  
  4832. http://codeforces.com/contest/908/problem/D (5) //[DP][MATH][INVERSION]
  4833.  
  4834. 7821 - Elections (4) //[EASY][DP]
  4835.  
  4836. http://codeforces.com/gym/101620 {G}(5) //[VERY NICE][DIJKSTRA][EXPECTED VALUE]
  4837.  
  4838. http://codeforces.com/contest/110/problem/D (4) //[NICE][COMBINATORICS]
  4839.  
  4840. http://codeforces.com/contest/108/problem/D (4) //[NICE][SIMPLE][COMBINATORICS]
  4841.  
  4842. 7619 - Guessing the Dice Roll (5) //[NICE][AHO][MATRIX EXPO]
  4843.  
  4844. 7998 - Election (3) //Math works too [probability][DP]
  4845.  
  4846. LightOJ 1104 //Birthday Paradox
  4847.  
  4848. Gym 101064K [2016 USP Try-outs] //Birthday Paradox
  4849.  
  4850. 11762 UVA (5)
  4851.  
  4852. 11427 UVA (5)
  4853.  
  4854. 11348 UVA (2)
  4855.  
  4856. http://codeforces.com/contest/768/problem/D (4) //With DP
  4857.  
  4858. http://www.spoj.com/problems/IITWPC4J/ (4) //with DP
  4859.  
  4860. 10828 UVA (5) //Nice problem but bad statemend: Expected value of visits MC
  4861.  
  4862. 10777 UVA (4) //NICE &mdash; yet solvable with DP
  4863.  
  4864. http://codeforces.com/contest/839/problem/C (3) //NICE & Easy => Tree
  4865.  
  4866. http://www.spoj.com/problems/ZCR/ (3) //Easy (+DP)
  4867.  
  4868. http://www.spoj.com/problems/IITKWPCN/ (2) //Easy &mdash; Odd/Eve (black balls)
  4869.  
  4870. http://codeforces.com/contest/846/problem/F (5) // Expected number of unique elements
  4871.  
  4872. http://www.spoj.com/problems/BTCODE_H/ (4) //DP (but main GROW is idea)
  4873.  
  4874. http://codeforces.com/contest/867/problem/D (5) //VERY NICE [DP]
  4875.  
  4876. http://codeforces.com/contest/24/problem/D (5) //VERY NICE [DP]+[TIME]
  4877.  
  4878. http://codeforces.com/contest/28/problem/C (4) //VERY NICE [DP]
  4879.  
  4880. </spoiler>
  4881.  
  4882.  
  4883. <spoiler summary="recursion">
  4884.  
  4885. https://codeforces.com/contest/1175/problem/B (3) //[STACK]
  4886.  
  4887. https://www.codechef.com/problems/HPIRATES (4) //[VERY NICE][OBSERVATION][GRAPHS]
  4888.  
  4889. 8255 - Dunglish [LA] (3) //Finding all possibilities
  4890.  
  4891. http://codeforces.com/contest/915/problem/C (4) //[NICE][DP-works-too][GREEDY]
  4892.  
  4893. http://codeforces.com/contest/134/problem/B (4) //Number Theory
  4894.  
  4895. http://codeforces.com/contest/897/problem/C (4) //+Slightly [DP]
  4896.  
  4897. 6585 - Draughts (4) //[NICE][BACKTRACK][DFS]
  4898.  
  4899. http://codeforces.com/contest/68/problem/D (5) //[NICE] Keep max and kill branches
  4900.  
  4901. UVA 536 //Tree from dfs
  4902.  
  4903. UVA 12347 //BST from preorder
  4904.  
  4905. http://www.spoj.com/problems/GOC11A/ 4
  4906.  
  4907. 13170 UVA (7) //heavy implementation &mdash; but NICE!
  4908.  
  4909. 10854 UVA (3) //if/else
  4910.  
  4911. http://codeforces.com/contest/31/problem/D (4) //[NICE] Brute-force by recursion
  4912.  
  4913. http://codeforces.com/contest/36/problem/B (2) //[NICE][SIMPLE]
  4914.  
  4915. </spoiler>
  4916.  
  4917. <spoiler summary="RMQ">
  4918.  
  4919. https://www.spoj.com/problems/MOZPWS/ (4) //[NICE][IMPLEMENTATION][MQ]
  4920.  
  4921. https://codeforces.com/contest/1208/problem/E (5) //[VERY NICE][OFFLINE][ST]
  4922.  
  4923. https://codeforces.com/gym/101972/problem/G (4) //[NICE][SWEEP WORKS TOO]
  4924.  
  4925. http://codeforces.com/problemset/problem/514/D //+BS
  4926.  
  4927. http://codeforces.com/problemset/problem/872/B
  4928.  
  4929. http://www.spoj.com/problems/TNVFC1M/
  4930.  
  4931. https://devskill.com/CodingProblems/ViewProblem/19
  4932.  
  4933. http://codeforces.com/contest/713/problem/D 6
  4934.  
  4935. http://codeforces.com/contest/675/problem/E 5
  4936.  
  4937. http://www.spoj.com/problems/POSTERIN/ 5 //VERY NICE &mdash; Delete all minimas
  4938.  
  4939. http://www.spoj.com/problems/RPLN/ (3) //RMQ only
  4940.  
  4941. http://www.spoj.com/problems/CITY2/ (4) //RMQ + MAP [NICE][VAGUE STATEMENT]
  4942.  
  4943. http://www.spoj.com/problems/DIFERENC/ (4) //Solve separately (linear D&C)
  4944.  
  4945. http://codeforces.com/contest/863/problem/E (4) //OR some Queue / sorting
  4946.  
  4947. http://codeforces.com/contest/5/problem/C (4) //NICE &mdash; many other options
  4948.  
  4949. http://codeforces.com/contest/15/problem/D (5) //VERY NICE 2D RM [sliding-windw][monotone-queue]
  4950.  
  4951. http://codeforces.com/contest/873/problem/E (5) //[NICE][Brute-Force + RMQ]
  4952.  
  4953. </spoiler>
  4954.  
  4955. <spoiler summary="rope">
  4956.  
  4957. http://www.spoj.com/problems/AROPE/ 4
  4958.  
  4959. http://www.spoj.com/problems/AROPE2/ 5 //same as above (+time)
  4960.  
  4961. </spoiler>
  4962.  
  4963. <spoiler summary="scc">
  4964.  
  4965. http://www.spoj.com/problems/ADAPANEL/ [combinatorics]
  4966.  
  4967. 13301 - Impossible Communication (4) //[CUTE][SAMPLE][OBSERVATION][EASY]
  4968.  
  4969. http://codeforces.com/problemset/problem/427/C proposed by [user:unofficial10]
  4970.  
  4971. http://codeforces.com/contest/894/problem/E (5) //[NICE][DP]
  4972.  
  4973. https://devskill.com/CodingProblems/ViewProblem/79
  4974.  
  4975. UVA 11838
  4976.  
  4977. UVA 247
  4978.  
  4979. UVA 13057
  4980.  
  4981. UVA 12645
  4982.  
  4983. UVA 11770
  4984.  
  4985. UVA 12926
  4986.  
  4987. UVA 11324
  4988.  
  4989. UVA 11709
  4990.  
  4991. UVA 12745
  4992.  
  4993. http://www.spoj.com/problems/TFRIENDS/ (4) //just scc size
  4994.  
  4995. http://www.spoj.com/problems/CAPCITY/ (4) //scc destination [WEAK TC]
  4996.  
  4997. http://codeforces.com/contest/22/problem/E (5) //[NICE][make it strongly connected][SRC>DST]
  4998.  
  4999. </spoiler>
  5000.  
  5001. <spoiler summary="segment_tree">
  5002.  
  5003. http://www.spoj.com/problems/ADABERRY/ [+TREAP]
  5004.  
  5005. https://codeforces.com/gym/102307/problem/E (5) //[SWEEP]
  5006.  
  5007. https://codeforces.com/contest/1208/problem/D (5) //[NICE][GREEDY][BS]
  5008.  
  5009. https://codeforces.com/contest/1180/problem/E (6) //[VERY NICE]
  5010.  
  5011. https://codeforces.com/contest/1187/problem/D (5) //[VERY NICE][GREEDY][STACK]
  5012.  
  5013. https://toph.co/p/maintain-the-queue (5) //[NICE][QUEUE]
  5014.  
  5015. http://codeforces.com/gym/101992/problem/L (5) //[VERY NICE]
  5016.  
  5017. http://codeforces.com/gym/101982 [F] (6) //[SWEEP][NORMALIZE][NICE][XOR]
  5018.  
  5019. http://codeforces.com/gym/101962/problem/I (4) //[BS]
  5020.  
  5021. http://codeforces.com/gym/101801 [G] (5) //Two ST [SEQUENCE]
  5022.  
  5023. http://codeforces.com/gym/101879/problem/G (5) //Merge / Special
  5024.  
  5025. http://codeforces.com/gym/101741/problem/J (6) //[NICE][COMBINATORICS]
  5026.  
  5027. http://codeforces.com/contest/914/problem/D (5) //[NICE][GCD][LOG]
  5028.  
  5029. http://codeforces.com/contest/915/problem/E (5) //[VERY NICE][UNLIMITED]
  5030.  
  5031. http://codeforces.com/contest/145/problem/E (5) //[NICE]//Bit swap + subsequence
  5032.  
  5033. http://www.spoj.com/problems/ADAGF/
  5034.  
  5035. http://www.spoj.com/problems/ADATREE/
  5036.  
  5037. http://codeforces.com/contest/911/problem/G (7) //Segment tree over queries
  5038.  
  5039. http://codeforces.com/contest/895/problem/E (5) //[PRECISION]
  5040.  
  5041. http://codeforces.com/contest/52/problem/C (4) //Easy [MIN]+[INCREASE]
  5042.  
  5043. http://codeforces.com/contest/56/problem/E (5) //[NICE][NORMALIZE][MAX]
  5044.  
  5045. http://codeforces.com/contest/877/problem/E (5) //[VERY NICE][EULER TOUR TREE]
  5046.  
  5047. https://devskill.com/CodingProblems/ViewProblem/283
  5048.  
  5049. https://devskill.com/CodingProblems/ViewProblem/315
  5050.  
  5051. http://codeforces.com/problemset/problem/756/C
  5052.  
  5053. http://codeforces.com/contest/739/problem/C (8)
  5054.  
  5055. http://codeforces.com/contest/718/problem/C (8)
  5056.  
  5057. http://codeforces.com/contest/750/problem/E (7)
  5058.  
  5059. http://codeforces.com/contest/759/problem/C (7)
  5060.  
  5061. 11165 UVA (5)
  5062.  
  5063. http://codeforces.com/contest/763/problem/E (8) //VERY NICE &mdash; [non-trivial]
  5064.  
  5065. http://www.spoj.com/problems/BGSHOOT/ (5) //normalize &mdash; then easy
  5066.  
  5067. http://www.spoj.com/problems/KGSS/ (4)
  5068.  
  5069. http://codeforces.com/contest/765/problem/F (7) //VERY NICE &mdash; CASCADE
  5070.  
  5071. http://www.spoj.com/problems/GSS1/ (5) //Idea &mdash; then easy
  5072.  
  5073. http://www.spoj.com/problems/KQUERYO/ (5) //Seg-tree of vectors
  5074.  
  5075. http://codeforces.com/contest/633/problem/G (8) //EulerTree+Seg+Bitset
  5076.  
  5077. http://www.spoj.com/problems/NAJ0001/ (7) //10^8 int &mdash; memory (and worked)
  5078.  
  5079. http://www.spoj.com/problems/PRMQUER/ (5) //2 segment trees + sieve
  5080.  
  5081. http://www.spoj.com/problems/EC_DIVS/ (5) //dunno if intended
  5082.  
  5083. http://www.spoj.com/problems/DCEPC11I/ (5) //NICE &mdash; 1,2,3,4,5,.. inc
  5084.  
  5085. http://www.spoj.com/problems/QUE2/ (4) //kth number
  5086.  
  5087. http://codeforces.com/contest/785/problem/E (6) //Seg+Treap [and faster]
  5088.  
  5089. http://codeforces.com/contest/786/problem/B (6) //+Dijkstra
  5090.  
  5091. 13183 UVA (6) //Merge-Sort-Tree [dunno]
  5092.  
  5093. http://codeforces.com/contest/121/problem/E (7) //Dunno - done by vectorisation
  5094.  
  5095. http://codeforces.com/contest/803/problem/G (5) //VERY NICE!! &mdash; ST 10^9 + ST/RMQ 10^5
  5096.  
  5097. http://codeforces.com/contest/794/problem/F (7) //Digit by digit! (N*log(N)*100 ~passes,2017-10-19)
  5098.  
  5099. http://codeforces.com/contest/811/problem/E (6) //VERY NICE &mdash; DSU (easier Timofey + animals)
  5100.  
  5101. http://codeforces.com/contest/817/problem/F (7) //10^18 + MEX ~~ NICE yet problematic
  5102.  
  5103. http://codeforces.com/contest/816/problem/B (3) //Or offline trick makes it easier
  5104.  
  5105. http://codeforces.com/contest/834/problem/D (5) //+Dynamic Programming | NICE
  5106.  
  5107. http://www.spoj.com/problems/SBO/ (5) //preLast→ last (-1), last→ now (+1) &mdash; VERY NICE
  5108.  
  5109. http://www.spoj.com/problems/GOODE/ (5) //NICE: Inversion + L-Mex
  5110.  
  5111. http://www.spoj.com/problems/CNTPRIME/ (3) //ST+Sieve (short range)
  5112.  
  5113. http://www.spoj.com/problems/SEGSQRSS/ (4) //NICE {weak data} ~~ SQRT works too
  5114.  
  5115. http://www.spoj.com/problems/MON2012/ (5) //NICE [Online][10^9 Range]
  5116.  
  5117. http://www.spoj.com/problems/PARSUMS/ (4) //But other approaches work too
  5118.  
  5119. http://www.spoj.com/problems/THRBL/ (4) //Simple SA &mdash; maximum on range <= A[a]
  5120.  
  5121. http://www.spoj.com/problems/HORRIBLE/ (3) //Totally classical
  5122.  
  5123. http://www.spoj.com/problems/MULTQ3/ (4) //NICE (interesting operation)
  5124.  
  5125. http://www.spoj.com/problems/PERMPATT/ (4) //NICE [minimum][+IDEA]
  5126.  
  5127. http://codeforces.com/contest/869/problem/E (5) //NICE &mdash; 2D [random][XOR]
  5128.  
  5129. http://codeforces.com/contest/19/problem/D (5) //NICE [+BS][+SET] {bs not necessary}
  5130.  
  5131. </spoiler>
  5132.  
  5133. <spoiler summary="sequences">
  5134.  
  5135. 11885 UVA 7 //Previous problem requested for statement
  5136.  
  5137. 11522 UVA 3 //Trick &mdash; low numbers only :P
  5138.  
  5139. https://codeforces.com/contest/1208/problem/A (2) //First few terms :)
  5140.  
  5141. </spoiler>
  5142.  
  5143. <spoiler summary="sieve">
  5144.  
  5145. http://www.spoj.com/problems/ADAPRIME/
  5146.  
  5147. https://devskill.com/CodingProblems/ViewProblem/577 (4) //[NICE][TWO POINTERS]
  5148.  
  5149. https://www.spoj.com/problems/EVENSEMIP/ (5) //[VERY NICE][SEGMENTED]
  5150.  
  5151. http://codeforces.com/gym/101982 [H] (3) //[GOLDBACH]
  5152.  
  5153. http://codeforces.com/contest/114/problem/E (5) //[NICE][FAST THINGS NEEDED][SEGMENTED]
  5154.  
  5155. http://codeforces.com/contest/58/problem/B (3) //[NICE][GREEDY][LEAST PRIME FACTOR]
  5156.  
  5157. Project Euler #134: Prime pair connection //Segmented
  5158.  
  5159. 11610 UVA (5)
  5160.  
  5161. 11353 UVA (3)
  5162.  
  5163. http://www.spoj.com/problems/TDPRIMES/ (4)
  5164.  
  5165. http://www.spoj.com/problems/VECTAR8/ (3)
  5166.  
  5167. http://www.spoj.com/problems/NFACTOR/ (4)
  5168.  
  5169. http://www.spoj.com/problems/HS08PAUL/ (4) //simply generate
  5170.  
  5171. http://codeforces.com/contest/776/problem/B (3) //Easy &mdash; trict: PM-1/ELSE-2
  5172.  
  5173. http://www.spoj.com/problems/GGD/ (4) // N/lowestDiv*(lowestDiv-1)
  5174.  
  5175. http://codeforces.com/contest/822/problem/D (4) //DP + Lowest factor
  5176.  
  5177. http://www.spoj.com/problems/NGIRL/ (4) //Squares &mdash; Primes + BS == Easiest
  5178.  
  5179. http://www.spoj.com/problems/PTRI/ (5) //Very fast sieve necessary:/
  5180.  
  5181. http://www.spoj.com/problems/AFS/ (3) //Sum of divisort + DP
  5182.  
  5183. http://www.spoj.com/problems/BSPRIME/ (4) //Very fast sieve needed
  5184.  
  5185. http://www.spoj.com/problems/DCEPC505/ (4) //NICE &mdash; at most 10527450
  5186.  
  5187. http://www.spoj.com/problems/CUBEFR/ (3) //NICE &mdash; Sieve out k^3 numbers
  5188.  
  5189. http://www.spoj.com/problems/PRIMES2/ (8) //VERY NICE &mdash; Some hell-shit optimizing
  5190.  
  5191. http://codeforces.com/contest/26/problem/A (2) //Easy &mdash; many ways to solve it
  5192.  
  5193. </spoiler>
  5194.  
  5195. <spoiler summary="simulation">
  5196.  
  5197. https://codeforces.com/contest/1169/problem/A (2) //Ifs shall work too
  5198.  
  5199. https://codeforces.com/contest/1180/problem/C (4) //[MODULO][QUEUE]
  5200.  
  5201. https://codeforces.com/gym/102001/problem/F (4) //[NICE][GREEDY]
  5202.  
  5203. https://codeforces.com/gym/101991/problem/D (4) //[NICE][NORMALIZE][PREFIX]
  5204.  
  5205. https://codeforces.com/gym/102021 [L] (5) //[NICE][JUST DO IT]
  5206.  
  5207. https://codeforces.com/gym/102021 [D] (4) //Try one and see
  5208.  
  5209. https://codeforces.com/gym/101972/problem/K (3) //[EASY][STRINGS]
  5210.  
  5211. http://codeforces.com/gym/101962/problem/K (3) //[NICE] //Complexity
  5212.  
  5213. http://codeforces.com/gym/101650 [A](7) //[VERY NICE][TREAP][PROBABILITY]
  5214.  
  5215. http://codeforces.com/gym/101650 [K](5) //[NICE] //Perhaps weak TC
  5216.  
  5217. https://abc084.contest.atcoder.jp/tasks/abc084_c (3) //Brute-Force
  5218.  
  5219. http://codeforces.com/contest/908/problem/B (2) //[EASY][NICE]
  5220.  
  5221. http://codeforces.com/contest/141/problem/B (3) //[NICE][IF-PARTY]
  5222.  
  5223. 7921 - Anticlockwise Motion (4) //Simulate in sqrt
  5224.  
  5225. 7691 - Falling Apples (3)
  5226.  
  5227. 7977 - The Key to Cryptography (2)
  5228.  
  5229. http://codeforces.com/contest/129/problem/B (2) //Graph
  5230.  
  5231. http://codeforces.com/contest/903/problem/B (2) //[NICE]
  5232.  
  5233. http://codeforces.com/contest/120/problem/C (1)
  5234.  
  5235. http://codeforces.com/contest/118/problem/A (1)
  5236.  
  5237. 8012 - Voting Fraud (1)
  5238.  
  5239. http://codeforces.com/contest/897/problem/A (1) //BF - do as they say
  5240.  
  5241. 7985 - Bumper-to-Bumper Traffic (4) //FINE - We have whole time-lapse
  5242.  
  5243. 7988 Flow Shop (3) //Do as they say. Trivial but not bad.
  5244.  
  5245. 7703 - Reading Digits (2) //Simple simulate what they ask for
  5246.  
  5247. http://codeforces.com/contest/893/problem/A (1) //Easy but nice
  5248.  
  5249. http://codeforces.com/contest/102/problem/B (2) //Do as they write - log-convergence
  5250.  
  5251. http://codeforces.com/contest/92/problem/A (1) //Way too easy
  5252.  
  5253. http://codeforces.com/contest/88/problem/C (3) //[NUMBER THEORY]
  5254.  
  5255. http://codeforces.com/contest/84/problem/D (4) //Priority queue by min*size
  5256.  
  5257. http://codeforces.com/contest/79/problem/A (1) //Simulate rules
  5258.  
  5259. http://codeforces.com/contest/879/problem/A (1) //Iterate day-by-day
  5260.  
  5261. http://codeforces.com/contest/879/problem/B (3) //Either at most N^2 or the biggest element [NICE]
  5262.  
  5263. http://codeforces.com/contest/879/problem/D (4) //[NICE][Array elimination]
  5264.  
  5265. http://codeforces.com/contest/46/problem/A (2) //[EASY][MODULO]
  5266.  
  5267. http://codeforces.com/contest/46/problem/B (3) //[EASY][SEARCH-EACH-QUERY]
  5268.  
  5269. http://codeforces.com/contest/55/problem/A (2) //Simple (long) simulation
  5270.  
  5271. http://codeforces.com/contest/60/problem/A (1) //Moving LR bounds
  5272.  
  5273. 12187 UVA (2)
  5274.  
  5275. http://codeforces.com/contest/724/problem/C 5
  5276.  
  5277. http://codeforces.com/contest/746/problem/C 3
  5278.  
  5279. 11093 UVA (2)
  5280.  
  5281. http://codeforces.com/contest/768/problem/C (4)
  5282.  
  5283. http://www.spoj.com/problems/WRONG/ (5) //VERY NICE &mdash; precalculate from back, then go from front
  5284.  
  5285. http://codeforces.com/contest/864/problem/C (4) //Not nice &mdash; just iffs
  5286.  
  5287. http://www.spoj.com/problems/WAGE/ (3) //Simple Game Of Life Modification
  5288.  
  5289. http://codeforces.com/contest/6/problem/C (2) //Simple simulate from both sides
  5290.  
  5291. http://codeforces.com/contest/9/problem/B (2) //Simulate what is given (+ doubles)
  5292.  
  5293. http://codeforces.com/contest/11/problem/B (3) //sqrt(X) [diff must be even]
  5294.  
  5295. http://codeforces.com/contest/30/problem/A (2) //Simply simulate process [-1000→ 1000]
  5296.  
  5297. </spoiler>
  5298.  
  5299. <spoiler summary="sorting">
  5300.  
  5301. http://www.spoj.com/problems/ADATOMAT/
  5302.  
  5303. http://www.spoj.com/problems/ADAUSORT/
  5304.  
  5305. http://www.spoj.com/problems/ADACUT/
  5306.  
  5307. http://www.spoj.com/problems/ADAHLIA/
  5308.  
  5309. https://codeforces.com/contest/1148/problem/D (4) //[NICE][GREEDY]
  5310.  
  5311. https://codeforces.com/contest/1174/problem/B (3) //[OBSERVATION] Nice yet simple
  5312.  
  5313. https://codeforces.com/contest/1174/problem/A (2) //[EASY]
  5314.  
  5315. https://codeforces.com/contest/1203/problem/E (4) //[GREEDY][SIMPLE]
  5316.  
  5317. https://codeforces.com/contest/1203/problem/B (3) //[GREEDY][NICE]
  5318.  
  5319. https://codeforces.com/contest/1185/problem/D (4) //[BF][IMPLE][MATH]
  5320.  
  5321. https://codeforces.com/contest/1185/problem/C1 (3) //[GREEDY]
  5322.  
  5323. https://codeforces.com/contest/1197/problem/C (4) //[NICE][EASY][OBSERVATION]
  5324.  
  5325. https://codeforces.com/contest/1197/problem/A (3) //[SIMPLE][GREEDY][MATH]
  5326.  
  5327. https://codeforces.com/contest/1189/problem/B (3) //[EASY][OBSERVATION]
  5328.  
  5329. https://www.spoj.com/problems/SWAPDIFF1/ (4) //[CLASSICAL][INVERSIONS]
  5330.  
  5331. https://www.spoj.com/problems/SHINCARD/ (4) //[NICE]
  5332.  
  5333. https://www.spoj.com/problems/POTATOPL/ (4) //[NICE][GREEDY]
  5334.  
  5335. https://codeforces.com/gym/101991/problem/I (3)
  5336.  
  5337. http://codeforces.com/gym/101962/problem/M (4)
  5338.  
  5339. http://codeforces.com/gym/101726/problem/E (3) //[STRUCTURES][IMPLEMENTATION]
  5340.  
  5341. 13282 Cakey McCakeFace (3) //Brute Force
  5342.  
  5343. 8260 Installing Apps (4) //[NICE] //Sorting + some DP
  5344.  
  5345. http://codeforces.com/contest/922/problem/D (3) //[NICE][GREEDY][EASY]
  5346.  
  5347. http://codeforces.com/contest/920/problem/C (3) //[EASY] Sortable by parts
  5348.  
  5349. http://codeforces.com/contest/913/problem/D (4) //[NICE][BS][2P][FW]
  5350.  
  5351. http://codeforces.com/contest/149/problem/A (2) //Sorting|Greedy
  5352.  
  5353. http://www.spoj.com/problems/SEUG/ (2) //Bad statement
  5354.  
  5355. http://codeforces.com/contest/141/problem/A (2) //Or frequency
  5356.  
  5357. http://codeforces.com/contest/137/problem/E (4) //[NICE][PREFIX SUM MATCHING]
  5358.  
  5359. http://codeforces.com/contest/137/problem/C (4) //[NICE][FENWICK WORKS TOO]
  5360.  
  5361. http://codeforces.com/contest/136/problem/C (3) //Last to 1(2) |OR| first to INF
  5362.  
  5363. 7601 - Football (3) //Greedy
  5364.  
  5365. 7673 - What a Simple Research (2) //[EASY][IMPLE]
  5366.  
  5367. http://codeforces.com/contest/108/problem/B (2) //Easy & Adjacent
  5368.  
  5369. 8025 - Stacking Cups (2) //Sorting+input
  5370.  
  5371. http://codeforces.com/contest/892/problem/A (2) //[EASY][SUM]
  5372.  
  5373. https://www.urionlinejudge.com.br/judge/en/problems/view/2290 (3) //Sort+check [fast]
  5374.  
  5375. http://codeforces.com/contest/81/problem/C (3) //MATH[Lesser=greater][comparator]
  5376.  
  5377. http://codeforces.com/contest/53/problem/D (3) //Bubble sort
  5378.  
  5379. http://codeforces.com/contest/58/problem/D (4) //[BUCKET][GREEDY][STRING]
  5380.  
  5381. UVA 10810 //INV
  5382.  
  5383. UVA 11858 //INV
  5384.  
  5385. http://codeforces.com/problemset/problem/645/B //INV
  5386.  
  5387. UVA 10327 //INV
  5388.  
  5389. http://www.spoj.com/problems/BUBBLESORT/ //INV
  5390.  
  5391. UVA 11495 //INV [GAME]
  5392.  
  5393. http://www.spoj.com/problems/CODESPTB/ //INV
  5394.  
  5395. UVA 13212 //INV
  5396.  
  5397. http://codeforces.com/problemset/problem/749/E //INV
  5398.  
  5399. 12189 UVA (3)
  5400.  
  5401. 12196 UVA (4)
  5402.  
  5403. http://codeforces.com/contest/731/problem/D 7
  5404.  
  5405. 11925 UVA (4)
  5406.  
  5407. 11979 UVA (3)
  5408.  
  5409. http://codeforces.com/contest/747/problem/D (4)
  5410.  
  5411. 11890 UVA (4)
  5412.  
  5413. http://www.spoj.com/problems/KAOS/ (4) //INV &mdash; GOOD problem!!!!
  5414.  
  5415. http://www.spoj.com/problems/KSMALL/ (5) //fast sort /or/ quick-select
  5416.  
  5417. http://www.spoj.com/problems/RKS/ (3) //use map
  5418.  
  5419. http://www.spoj.com/problems/SPCJ/ (4) //reverse + go from back
  5420.  
  5421. http://codeforces.com/contest/785/problem/B (2) //last-first + vice versa
  5422.  
  5423. http://codeforces.com/contest/798/problem/D (4) //Take 1st then take best B of every pair (sort by A)
  5424.  
  5425. http://codeforces.com/contest/810/problem/B (2)
  5426.  
  5427. http://codeforces.com/contest/810/problem/C (3) //+Math
  5428.  
  5429. http://codeforces.com/contest/814/problem/A (1) //Pro prváky &mdash; but nice observation
  5430.  
  5431. http://codeforces.com/contest/817/problem/B (3) //Frequency of TOP 3
  5432.  
  5433. 10769 UVA (3) //Sadly N^4 passes
  5434.  
  5435. 13208 UVA (4) //Sort + Prefix Sum
  5436.  
  5437. 13212 UVA (3) //Number of inversions
  5438.  
  5439. http://codeforces.com/contest/831/problem/C (3) //NICE ~ Check all "add" against first
  5440.  
  5441. http://codeforces.com/contest/831/problem/D (4) //Can be solved with BS+Max-Match
  5442.  
  5443. http://codeforces.com/contest/841/problem/C (3) //NICE &mdash; match greatest to lowest
  5444.  
  5445. http://codeforces.com/contest/845/problem/C (2) //EASY &mdash; pro prvaky
  5446.  
  5447. http://www.spoj.com/problems/HSHW/ (4) //Test every big/low pair + big/big low/low on +/-
  5448.  
  5449. http://www.spoj.com/problems/CODESPTB/ (3) //Count inversions [BASIC]
  5450.  
  5451. http://codeforces.com/contest/863/problem/B (2) //Sort and omit 2
  5452.  
  5453. http://www.spoj.com/problems/AMR10G/ (2) //Easy yet NICE
  5454.  
  5455. http://codeforces.com/contest/12/problem/C (2) //Very simple
  5456.  
  5457. http://codeforces.com/contest/16/problem/B (1) //[EASY]
  5458.  
  5459. http://codeforces.com/contest/22/problem/D (3) //Sort by begin + sweep
  5460.  
  5461. http://codeforces.com/contest/23/problem/C (3) //Take them by pairs + add last
  5462.  
  5463. http://codeforces.com/contest/24/problem/B (3) //Simple follow the rules
  5464.  
  5465. http://codeforces.com/contest/27/problem/B (3) //Compare number of victories
  5466.  
  5467. http://codeforces.com/contest/27/problem/C (4) //[NICE] Find next bigger/lesser (sort)
  5468.  
  5469. </spoiler>
  5470.  
  5471. <spoiler summary="spanning_tree">
  5472.  
  5473. https://www.urionlinejudge.com.br/judge/en/problems/view/2683 (3) //[BASIC][MAXIMUM]
  5474.  
  5475. http://codeforces.com/contest/908/problem/F (5) //[VERY NICE] //Not exactly MST but similar[GREEDY]
  5476.  
  5477. http://codeforces.com/contest/125/problem/E (5) //[BS]
  5478.  
  5479. http://codeforces.com/contest/76/problem/A (4) //[VERY NICE] Sort by A and KEEP spanning + one edge
  5480.  
  5481. LA 6622 - Absurdistan Roads (4) //Plus one edge
  5482.  
  5483. UVA 12176
  5484.  
  5485. UVA 10600
  5486.  
  5487. UVA 10724
  5488.  
  5489. https://www.hackerrank.com/contests/june-world-codesprint/challenges/johnland
  5490.  
  5491. UVA 11710
  5492.  
  5493. Gym 101252C [2014-2015 CT S02E05: Codeforces Trainings Season 2 Episode 5 &mdash; 2009-2010 ACM-ICPC]
  5494.  
  5495. Gym 101047I [2015 USP Try-outs][HARD]
  5496.  
  5497. UVA 11183 [Directed]
  5498.  
  5499. LightOJ 1101
  5500.  
  5501. https://www.codechef.com/problems/CHEFELEC
  5502.  
  5503. UVA 10307
  5504.  
  5505. http://codeforces.com/problemset/problem/598/D
  5506.  
  5507. http://codeforces.com/problemset/problem/32/C
  5508.  
  5509. http://codeforces.com/problemset/problem/744/A
  5510.  
  5511. https://devskill.com/CodingProblems/ViewProblem/344
  5512.  
  5513. 908 &mdash; Re-connecting Computer Sites [UVA]
  5514.  
  5515. 1208 &mdash; Oreon [UVA]
  5516.  
  5517. 1235 &mdash; Anti Brute Force Lock [UVA]
  5518.  
  5519. 10034 &mdash; Freckles [UVA]
  5520.  
  5521. 11228 &mdash; Transportation system [UVA]
  5522.  
  5523. 11631 &mdash; Dark roads [UVA]
  5524.  
  5525. 11733 &mdash; Airports [UVA]
  5526.  
  5527. 11747 &mdash; Heavy Cycle Edges [UVA]
  5528.  
  5529. BLINNET SPOJ (3)
  5530.  
  5531. 11183 UVA (4) //Directed [need to know algo!]
  5532.  
  5533. http://www.spoj.com/problems/ULM09/ (3) //Sum-Kruskal
  5534.  
  5535. http://www.spoj.com/problems/IITKWPCG/ (4) //VERY NICE [log instead of price]
  5536.  
  5537. http://codeforces.com/contest/17/problem/B (3) //Spanning tree [no dsu]
  5538.  
  5539. </spoiler>
  5540.  
  5541. <spoiler summary="spfa">
  5542.  
  5543. LightOJ 1074
  5544.  
  5545. UVA 1171
  5546.  
  5547. UVA 11478
  5548.  
  5549. UVA 12768
  5550.  
  5551. 11478 UVA (5)
  5552.  
  5553. </spoiler>
  5554.  
  5555. <spoiler summary="sqrt">
  5556.  
  5557. https://codeforces.com/gym/102307/problem/J (5) //[NICE]
  5558.  
  5559. https://codeforces.com/contest/1207/problem/F (5) //[VERY NICE][MODULO][SIEVE-LIKE]
  5560.  
  5561. https://codeforces.com/contest/1199/problem/D (4) //[NICE][SIMPLE IMPLE]
  5562.  
  5563. https://www.spoj.com/problems/ZING01/ (5) //[VERY NICE][STRING][SEGMENT]
  5564.  
  5565. http://codeforces.com/gym/101889 [D] (6) //[NICE][STL]
  5566.  
  5567. http://codeforces.com/contest/916/problem/D (6) //[NICE][BS][BINARY-LIFTING]
  5568.  
  5569. 12003 UVA 7
  5570.  
  5571. 11990 UVA (5)
  5572.  
  5573. http://www.spoj.com/problems/GIVEAWAY/ (7) //SQRT + BS > [or Seg+Trie]
  5574.  
  5575. http://codeforces.com/contest/786/problem/C (5) //Nsqrn (bg) + sqrSegs (end)
  5576.  
  5577. http://codeforces.com/contest/840/problem/D (5) //NICE &mdash; Either frequent OR brute-force
  5578.  
  5579. http://codeforces.com/contest/13/problem/E //VERY NICE [SQRT-BLOCK UPDATE/JUMP]
  5580.  
  5581. http://codeforces.com/contest/85/problem/D (4) //NICE [ST shall work too]
  5582.  
  5583. </spoiler>
  5584.  
  5585. <spoiler summary="stl">
  5586.  
  5587. http://www.spoj.com/problems/ADABASET/ [IO-testing][ARRAY]
  5588.  
  5589. http://www.spoj.com/problems/ADALIST/ [ROPE]
  5590.  
  5591. http://www.spoj.com/problems/ADAFIELD/ [SET]
  5592.  
  5593. http://www.spoj.com/problems/ADAQUEUE/
  5594.  
  5595. http://www.spoj.com/problems/ADAFRIEN/
  5596.  
  5597. https://codeforces.com/contest/1208/problem/B (3) //[NICE][TWO-POINTERS][BF]
  5598.  
  5599. https://www.spoj.com/problems/REDARR2/ (4) //[NICE][PQ]
  5600.  
  5601. https://www.spoj.com/problems/MINSTOCK/ (3) //[EASY][MAP]
  5602.  
  5603. http://codeforces.com/gym/101864 [F] (4) //[SET]
  5604.  
  5605. http://codeforces.com/contest/920/problem/B (3) //[NICE][QUEUE][SIMPLE]
  5606.  
  5607. http://codeforces.com/contest/911/problem/E (4) //[NICE][STACK][SET]
  5608.  
  5609. http://codeforces.com/contest/909/problem/D (4) //[VERY NICE][SIMULATION][GROUP]
  5610.  
  5611. http://codeforces.com/contest/899/problem/E (4) //[VERY NICE][SET]
  5612.  
  5613. https://arc087.contest.atcoder.jp/tasks/arc087_a (2) //Map
  5614.  
  5615. http://codeforces.com/contest/903/problem/C (2) //Map
  5616.  
  5617. http://codeforces.com/contest/900/problem/C (3) //[NICE][SET]
  5618.  
  5619. http://codeforces.com/contest/112/problem/A (1) //tolower [trivial]
  5620.  
  5621. 3396 - Alphabetics (2) //Getline, letters identification
  5622.  
  5623. http://codeforces.com/contest/81/problem/A (2) //Stack OR string
  5624.  
  5625. http://codeforces.com/contest/78/problem/A (1) //fgets + imple
  5626.  
  5627. http://codeforces.com/contest/69/problem/E (3) //NICE [2POINTERS][SET][MAP]
  5628.  
  5629. http://www.spoj.com/problems/RMID/ //Dynamic Median
  5630.  
  5631. http://www.spoj.com/problems/RMID2/ //Dynamic Median
  5632.  
  5633. http://codeforces.com/problemset/problem/713/C //Dynamic Median
  5634.  
  5635. http://www.spoj.com/problems/EC_ESTA/ //Dynamic median
  5636.  
  5637. http://codeforces.com/contest/799/problem/B (2) //EASY &mdash; MAP
  5638.  
  5639. http://codeforces.com/contest/808/problem/D (3) //MAP
  5640.  
  5641. 10887 (2) //string + map
  5642.  
  5643. 10730 (3) //Easy with hash-map
  5644.  
  5645. http://codeforces.com/contest/821/problem/C (3) //STACK (vector) Nice+Easy
  5646.  
  5647. http://www.spoj.com/problems/SOLVEIT/ (3) //Set + lower_bound
  5648.  
  5649. http://www.spoj.com/problems/IITKWPCA/ (2) //Set + getline
  5650.  
  5651. http://codeforces.com/contest/849/problem/D (5) //Queue
  5652.  
  5653. http://www.spoj.com/problems/CRAN02/ (4) //Map (+Math)
  5654.  
  5655. http://www.spoj.com/problems/MAX_NUM/ (4) //Queue (possibly multiple ways)
  5656.  
  5657. http://www.spoj.com/problems/SID/ (5) //Sort + Vector (or similar) [strict TLE]
  5658.  
  5659. http://www.spoj.com/problems/RPLD/ (2) //Map of sets
  5660.  
  5661. http://codeforces.com/contest/861/problem/D (4) //unordered map of sets
  5662.  
  5663. http://www.spoj.com/problems/FACEFRND/ (2) //Set or Bitset
  5664.  
  5665. http://www.spoj.com/problems/HACKRNDM/ (3) //Easy &mdash; map
  5666.  
  5667. http://codeforces.com/contest/847/problem/K (4) //NICE Map+Queue
  5668.  
  5669. http://codeforces.com/contest/855/problem/A (1) //set
  5670.  
  5671. http://codeforces.com/contest/4/problem/C (2) //map+string
  5672.  
  5673. http://codeforces.com/contest/5/problem/E (6) //iffs + RMQ+BS+SET [or other sol]
  5674.  
  5675. http://codeforces.com/contest/44/problem/A (1) //Set + pair
  5676.  
  5677. http://codeforces.com/contest/45/problem/C (4) //NICE &mdash; Handling with sets
  5678.  
  5679. http://codeforces.com/contest/918/problem/B (2) //[MAP] //TLDR
  5680.  
  5681. </spoiler>
  5682.  
  5683. <spoiler summary="strings">
  5684.  
  5685. https://codeforces.com/contest/1189/problem/A (2) //[OBSERVATION]
  5686.  
  5687. https://codeforces.com/contest/1194/problem/C (3) //[EASY][FREQUENCY][2POINTERS]
  5688.  
  5689. https://www.spoj.com/problems/MAGSUB1/ (3) //[EASY][SYMPATHIC][COMBINATORICS]
  5690.  
  5691. https://www.urionlinejudge.com.br/judge/en/problems/view/2866 (1) //Reverse
  5692.  
  5693. https://codeforces.com/gym/101972/problem/H (3) //[NICE][PREPROCESS]
  5694.  
  5695. http://codeforces.com/contest/909/problem/A (1) //Lexicographical comparision [EASY]
  5696.  
  5697. 7948 Periodic Strings (2) //Brute-force
  5698.  
  5699. 7892 - Game of Matchings (6) //No idea - heuristic works - but seems to be nice
  5700.  
  5701. 8017 - Mancunian and Sonu Generate Strings (5) //[NICE][DP]//+Something: Trie/SA/SET...?
  5702.  
  5703. http://codeforces.com/contest/890/problem/D (4) //[NICE][SET][SORTING][26][BRUTE-FORCE]
  5704.  
  5705. http://codeforces.com/contest/43/problem/B (2) //Frequency
  5706.  
  5707. http://codeforces.com/contest/50/problem/B (2) //Frequency + Power
  5708.  
  5709. http://www.spoj.com/problems/MINMOVE/ (3) //Minimal lexicographical rotation
  5710.  
  5711. http://www.spoj.com/problems/BWHEELER/ //Burrows Wheeler
  5712.  
  5713. http://www.spoj.com/problems/EDIST/ //Edit Distance
  5714.  
  5715. 3189 LA //Edit Distance
  5716.  
  5717. https://www.hackerrank.com/contests/morgan-stanley-2015/challenges/minimum-transformation-cost/problem //Edit Distance
  5718.  
  5719. http://codeforces.com/gym/101492/problem/L //Laevenstein Distance
  5720.  
  5721. UVA 13068 //Lexicographically lowest rotation
  5722.  
  5723. 2755 [LA]//Lexicographically lowest rotation
  5724.  
  5725. LightOJ 1073 //Lexicographically Shortest Superstring
  5726.  
  5727. http://codeforces.com/contest/762/problem/C 5
  5728.  
  5729. http://www.spoj.com/problems/LCS0/ 10 //LCS
  5730.  
  5731. http://www.spoj.com/problems/IITWPC4H/ 2 //Frequence array
  5732.  
  5733. 13186 UVA (6) //Bitset + Trie ~ NICE [6-7 mby?]
  5734.  
  5735. http://codeforces.com/contest/798/problem/B (2) //Brute-force .. pro prváky
  5736.  
  5737. 10745 UVA (4) //Frequency (N^2 possible if efficient!!)
  5738.  
  5739. http://codeforces.com/contest/822/problem/B (2) //Easy pro prvaky (slightly imple.)
  5740.  
  5741. http://codeforces.com/contest/828/problem/C (4) //+Sorting (process only necessary!)
  5742.  
  5743. http://codeforces.com/contest/832/problem/B (3) //Naive compare back+front [+freq]
  5744.  
  5745. http://www.spoj.com/problems/STC04/ (5) //Next + pairs O(N*26) [frist look O(26^2*N)]
  5746.  
  5747. http://www.spoj.com/problems/IITKWPCJ/ (4) //GCD or HASHING
  5748.  
  5749. http://www.spoj.com/problems/SUBSN/ (4) //Next (NICE &mdash; bad input):
  5750.  
  5751. http://www.spoj.com/problems/BOGGLE/ (2) //EASY [MAP][STREAM]
  5752.  
  5753. http://www.spoj.com/problems/MAIN8_E/ (4) //VERY NICE &mdash; Next function
  5754.  
  5755. http://www.spoj.com/problems/STRMATCH/ (3) //Nice matching, yet low constraints on "N"
  5756.  
  5757. http://www.spoj.com/problems/FINDSR/ (3) //Clever bruteforce works here (NlogN)
  5758.  
  5759. http://codeforces.com/contest/39/problem/J (2) //Simple iteration over string
  5760.  
  5761. http://codeforces.com/contest/876/problem/E (4) //Compare from back + make fail-pairs
  5762.  
  5763. </spoiler>
  5764.  
  5765. <spoiler summary="suffix_array">
  5766.  
  5767. http://www.spoj.com/problems/ADAPHOTO/ [or hashing after turboanalisis]
  5768.  
  5769. http://www.spoj.com/problems/ADASTRNG/
  5770.  
  5771. https://codeforces.com/gym/102302/problem/K (7) //[VERY NICE][TREAP][TWO POINTERS]
  5772.  
  5773. https://codeforces.com/contest/1202/problem/E (5) //[NICE][OBSERVATION][RMQ]
  5774.  
  5775. https://codeforces.com/gym/101991/problem/E (6) //[VERY NICE][RMQ]Prolly an easier alternative
  5776.  
  5777. https://toph.co/p/distinctness (6) //[VERY NICE][SET][LCP][RMQ]
  5778.  
  5779. http://codeforces.com/gym/101889 [M] (6) //[VERY NICE][OBSERVATION]
  5780.  
  5781. http://codeforces.com/gym/101840 [B] (7) //[NICE][ST][BIT][LCP]
  5782.  
  5783. http://codeforces.com/contest/129/problem/D (4) //[NICE]//Suffix Automaton / Brute Force works too
  5784.  
  5785. http://codeforces.com/contest/123/problem/D (5) //[NICE][RMQ][D&C]
  5786.  
  5787. 8086 Substring Sorting (7) //[VERY NICE][RMQ][BS][PST]
  5788.  
  5789. 7702 - Castle //6 [VERY NICE][RMQ][BS][FW]
  5790.  
  5791. 7701 - Favorite music //8 [VERY NICE][RMQ][SEARCH][OPTI] //WRONG TIME-LIMIT==OPTI
  5792.  
  5793. https://www.urionlinejudge.com.br/judge/en/problems/view/1530 //7 [VERY NICE][RMQ][SET][OFFLINE]
  5794.  
  5795. https://www.urionlinejudge.com.br/judge/en/problems/view/2000 (5) //Basic disubstr counting
  5796.  
  5797. UVA 760 //LCS
  5798.  
  5799. UVA 1227 //LCS
  5800.  
  5801. http://www.spoj.com/problems/LCS/en/ //LCS
  5802.  
  5803. UVA 11512
  5804.  
  5805. 7502 [LA]
  5806.  
  5807. Gym 100923D [2015 ACM National Contest Romania &mdash; Round 1]
  5808.  
  5809. UVA 1254
  5810.  
  5811. UVA 12191
  5812.  
  5813. UVA 12206
  5814.  
  5815. https://www.codechef.com/problems/INSQ16F
  5816.  
  5817. 3943 LA
  5818.  
  5819. UVA 11107
  5820.  
  5821. UVA 12974
  5822.  
  5823. UVA 10526
  5824.  
  5825. Davos and Reading [INSOMNIA] //Awesome problem but can't find link [hard] &mdash; non of regular judges
  5826.  
  5827. UVA 12338
  5828.  
  5829. https://devskill.com/CodingProblems/ViewProblem/328
  5830.  
  5831. 12191 UVA 5
  5832.  
  5833. SARRAY SPOJ 3
  5834.  
  5835. 4513 LA 6
  5836.  
  5837. http://www.spoj.com/problems/LCS2/ 7 // must be linear (SA+LCP+MQ)
  5838.  
  5839. http://codeforces.com/contest/802/problem/I 7 //NICE! SA+LCP+(Segmentree/queue)
  5840.  
  5841. http://www.spoj.com/problems/LONGCS/ //5 LCS of multiple strings (NICE)
  5842.  
  5843. http://www.spoj.com/problems/SUBLEX/ //5 VERY NICE: Kth substring
  5844.  
  5845. http://codeforces.com/contest/873/problem/F //6 VERY NICE: SA+Histogram
  5846.  
  5847. http://codeforces.com/contest/30/problem/E //7 VERY NICE: [many other sols: Manach/KMP/HASH...]
  5848.  
  5849. 6856 &mdash; Circle of digits //7 [VERY NICE]
  5850.  
  5851. </spoiler>
  5852.  
  5853.  
  5854. <spoiler summary="ternary_search">
  5855.  
  5856. LightOJ 1146
  5857.  
  5858. Gym 101482G [2014-2015 Northwestern European Regional Contest (NWERC 2014)]
  5859.  
  5860. Gym 101309D [2010-2011 ACM-ICPC Northeastern European Regional Contest (NEERC 10)]
  5861.  
  5862. UVA 13010 //+Dijkstra
  5863.  
  5864. 2015-2016 CTU Open Contest: Chasing the Cheetah
  5865.  
  5866. 12197 UVA (4)
  5867.  
  5868. http://www.spoj.com/problems/KOPC12A/ (4) //TS (sadly brute-force works too N^2)
  5869.  
  5870. </spoiler>
  5871.  
  5872. <spoiler summary="topo">
  5873.  
  5874. https://codeforces.com/gym/102058/problem/A (5) //[NICE][2TIMES][PRIORITY]
  5875.  
  5876. UVA 11686
  5877.  
  5878. LightOJ 1034
  5879.  
  5880. UVA 10305
  5881.  
  5882. 124 &mdash; Following Orders [UVA]
  5883.  
  5884. 200 &mdash; Rare Order [UVA]
  5885.  
  5886. 872 &mdash; Ordering [UVA]
  5887.  
  5888. 11060 &mdash; Beverages [UVA]
  5889.  
  5890. http://codeforces.com/contest/765/problem/E 5
  5891.  
  5892. http://codeforces.com/contest/770/problem/C 4 //reduce + toposort
  5893.  
  5894. http://codeforces.com/contest/825/problem/E 4 //Toposort from biggest/backward
  5895.  
  5896. http://www.spoj.com/problems/CODESPTI/ (6) //VERY NICE &mdash; Hard/Weak children
  5897.  
  5898. http://codeforces.com/contest/47/problem/B (2) //[EASY][Toposort on 3 elements]
  5899.  
  5900. http://codeforces.com/contest/909/problem/E (4) //[NICE][BFS][RECURSION]
  5901.  
  5902. </spoiler>
  5903.  
  5904. <spoiler summary="treap">
  5905.  
  5906. https://codeforces.com/contest/1181/problem/D (5) //[VERY NICE][SORTING][OFFLINE]
  5907.  
  5908. https://www.hackerrank.com/challenges/find-the-running-median/problem (4) //[NICE][HEAPS]
  5909.  
  5910. http://codeforces.com/gym/101992/problem/M (4) //[NICE][OFFLINE][SORTING]
  5911.  
  5912. http://codeforces.com/gym/100112 [C] (5) //[VERY NICE]
  5913.  
  5914. http://codeforces.com/gym/101864 [B] (5) //[NICE] Lesser than
  5915.  
  5916. http://codeforces.com/contest/899/problem/F (5) //[VERY NICE][DATA STRUCTURE] (FW or Treap)
  5917.  
  5918. http://codeforces.com/contest/879/problem/E (6) //[VERY NICE][Making somponents]
  5919.  
  5920. http://www.spoj.com/problems/ADAAPHID/ [or clever fenwick][or SQRT-tree]
  5921.  
  5922. http://www.spoj.com/problems/ADACROP/
  5923.  
  5924. http://codeforces.com/contest/762/problem/E 6
  5925.  
  5926. http://www.spoj.com/problems/COUNT1IT/ 5
  5927.  
  5928. http://www.spoj.com/problems/IITWPC4D/ 4 //From end &mdash; pick i-th + del i-th
  5929.  
  5930. http://www.spoj.com/problems/ALLIN1/ 4 //Typical treap operations
  5931.  
  5932. http://codeforces.com/contest/847/problem/D 5 //Prolly overkill &mdash; VERY NICE
  5933.  
  5934. http://codeforces.com/contest/863/problem/D 4 //Not desired solution
  5935.  
  5936. http://www.spoj.com/problems/KOILINE/ (4) //VERY NICE &mdash; Iterate from back &mdash; get+remove
  5937.  
  5938. http://www.spoj.com/problems/TWIST/ (5) //NICE: Reverse
  5939.  
  5940. http://www.spoj.com/problems/MEANARR/ (5) //VERY NICE! [POLICY][SHORT]
  5941.  
  5942. </spoiler>
  5943.  
  5944. <spoiler summary="tree">
  5945.  
  5946. http://www.spoj.com/problems/ADATOMEL/
  5947.  
  5948. https://codeforces.com/contest/1189/problem/D1 (4) //[OBSERVATION]
  5949.  
  5950. http://codeforces.com/contest/913/problem/B (2) //Simple check
  5951.  
  5952. http://codeforces.com/contest/894/problem/D (5) //[NICE][MERGING][BINARY]
  5953.  
  5954. http://codeforces.com/contest/746/problem/G 5
  5955.  
  5956. http://codeforces.com/contest/750/problem/F 9
  5957.  
  5958. http://www.spoj.com/problems/RTREE/ 3 //longest path tree &mdash; query
  5959.  
  5960. 13175 UVA (2) //something like preorder build
  5961.  
  5962. http://codeforces.com/contest/796/problem/C (3) //Just counting &mdash; inc by at most 2
  5963.  
  5964. http://codeforces.com/contest/797/problem/D (4) //VERY NICE &mdash; sort + D&C all
  5965.  
  5966. http://codeforces.com/contest/805/problem/E (4) //NICE &mdash; Treewidth coloring (greedy)
  5967.  
  5968. http://codeforces.com/contest/828/problem/D (3) //Star construction
  5969.  
  5970. http://www.spoj.com/problems/TREEDEGREE/ (3) //Degree from euler tree
  5971.  
  5972. http://www.spoj.com/problems/UCV2013J/ (3) //Find what is leaf in Binary Tree
  5973.  
  5974. http://www.spoj.com/problems/GCPC11J/ (3) //Finding ceter
  5975.  
  5976. http://codeforces.com/contest/34/problem/D (3) //Simple reconstruction + DFS
  5977.  
  5978. </spoiler>
  5979.  
  5980. <spoiler summary="tree-dp">
  5981.  
  5982. http://www.spoj.com/problems/ADASALES/
  5983.  
  5984. https://codeforces.com/contest/1187/problem/E (5) //[VERY NICE][DFS]
  5985.  
  5986. http://www.spoj.com/problems/PT07X/ (4) //Classical- VC on tree [NICE]
  5987.  
  5988. http://codeforces.com/contest/81/problem/E (6) //[NICE][PSEUDOFOREST REDUCTION]
  5989.  
  5990. http://codeforces.com/contest/61/problem/D (4) //dfs-only might works too
  5991.  
  5992. LA 6631 - Jingle Balls (4) //[NICE][SIMPLE]
  5993.  
  5994. https://www.codechef.com/problems/TRANDED //By [user:sahil070197]
  5995.  
  5996. 13089 &mdash; Golden Coins (UVA)
  5997.  
  5998. http://codeforces.com/problemset/problem/855/C
  5999.  
  6000. http://codeforces.com/problemset/problem/718/D
  6001.  
  6002. https://www.codechef.com/problems/TWOCOINS
  6003.  
  6004. https://www.hackerrank.com/contests/101hack35/challenges/road-maintenance/problem
  6005.  
  6006. 7649 &mdash; Performance Review (LA)
  6007.  
  6008. http://codeforces.com/problemset/problem/741/D
  6009.  
  6010. http://codeforces.com/problemset/problem/592/D
  6011.  
  6012. https://www.codechef.com/problems/TOMJERGA
  6013.  
  6014. http://codeforces.com/problemset/problem/814/D
  6015.  
  6016. 1220 &mdash; Party at Hali-Bula (UVA)
  6017.  
  6018. https://www.hackerrank.com/contests/june-world-codesprint/challenges/r-tree-decoration/problem
  6019.  
  6020. 12452 &mdash; Plants vs. Zombies HD SP (UVA)
  6021.  
  6022. http://codeforces.com/problemset/problem/735/E
  6023.  
  6024. https://www.codechef.com/problems/COLTREE
  6025.  
  6026. 12466 &mdash; Ancestors (UVA)
  6027.  
  6028. 6829 &mdash; Intrepid climber (LA)
  6029.  
  6030. https://www.hackerrank.com/contests/101hack35/challenges/jeanies-route
  6031.  
  6032. 12257 &mdash; The Queue (UVA)
  6033.  
  6034. http://codeforces.com/problemset/problem/805/F
  6035.  
  6036. http://codeforces.com/problemset/problem/763/D
  6037.  
  6038. 1218 &mdash; Perfect Service
  6039.  
  6040. 3346 &mdash; Perfect Domination on Trees (same as above -_-)
  6041.  
  6042. 12093 &mdash; Protecting Zonk
  6043.  
  6044. 10859 &mdash; Placing Lampposts
  6045.  
  6046. http://codeforces.com/problemset/problem/23/E //NICE [but requires big int]
  6047.  
  6048. http://codeforces.com/problemset/problem/14/D (5) //NICE [sorting-one][2DFS]
  6049.  
  6050. http://www.spoj.com/problems/TWOPATHS/ (6) //VERY NICE Same as above ~ bigger constraints
  6051.  
  6052. http://codeforces.com/contest/868/problem/E (8) //VERY NICE &mdash; HARD &mdash; on tree
  6053.  
  6054. </spoiler>
  6055.  
  6056. <spoiler summary="trie_bit">
  6057.  
  6058. https://www.spoj.com/problems/XORX/ (4) //[NICE][BASIC][PREFIXXOR]
  6059.  
  6060. http://codeforces.com/contest/888/problem/G (5) //NICE[BIT-BY-BIT D&C]
  6061.  
  6062. http://codeforces.com/contest/842/problem/D //Proposed by [user:usernameson]
  6063.  
  6064. http://codeforces.com/problemset/problem/706/D
  6065.  
  6066. https://www.hackerrank.com/contests/w8/challenges/black-box-1
  6067.  
  6068. https://csacademy.com/contest/round-42/task/xor-submatrix/
  6069.  
  6070. http://codeforces.com/contest/714/problem/C 5
  6071.  
  6072. http://www.spoj.com/problems/SUBXOR/ (4)
  6073.  
  6074. http://codeforces.com/contest/817/problem/E (5) //Classical &mdash; remember sum! NICE!
  6075.  
  6076. http://codeforces.com/contest/37/problem/C (4) //NICE &mdash; Prefix dictionary [or math]
  6077.  
  6078. </spoiler>
  6079.  
  6080. <spoiler summary="trie_string">
  6081.  
  6082. http://www.spoj.com/problems/ADAINDEX/
  6083.  
  6084. http://codeforces.com/gym/101628/problem/K (5) //[NICE][IMPLEMENTATION]
  6085.  
  6086. 8015 - Alice and Bob play Contact (5) //[VERY NICE] 1stBob
  6087.  
  6088. 2642 [LA]
  6089.  
  6090. UVA 10860
  6091.  
  6092. UVA 10295
  6093.  
  6094. UVA 13186 //+Bitset
  6095.  
  6096. UVA 1123
  6097.  
  6098. UVA 12506
  6099.  
  6100. UVA 11539
  6101.  
  6102. UVA 1142
  6103.  
  6104. UVA 12359
  6105.  
  6106. UVA 10282
  6107.  
  6108. 11732 UVA (5)
  6109.  
  6110. 11539 UVA (5)
  6111.  
  6112. 11488 UVA (4)
  6113.  
  6114. http://www.spoj.com/problems/TRYCOMP/ (4)
  6115.  
  6116. 10860 UVA (4) //DP + Trie [nice &mdash; slightly generic]
  6117.  
  6118. http://www.spoj.com/problems/DICT/ (4) //Sample trie &mdash; but slightly weak/wrong data-set
  6119.  
  6120. </spoiler>
  6121.  
  6122. <spoiler summary="TSP">
  6123.  
  6124. https://www.urionlinejudge.com.br/judge/en/problems/view/2810 (5) //[NICE][DOUBLE]
  6125.  
  6126. Gym 100818E [2015-2016 ACM-ICPC Southeastern European Regional Programming Contest (SEERC 2015)]
  6127.  
  6128. 3725 [LA]
  6129.  
  6130. UVA 10496
  6131.  
  6132. Gym 101020H [2015 Syrian Private Universities Collegiate Programming Contest] N!
  6133.  
  6134. LightOJ 1057
  6135.  
  6136. UVA 11643 //[NICE][BFS]
  6137.  
  6138. 3305 [LA] //On plane
  6139.  
  6140. 10937 UVA (4) //find '!' / BFS / TSP &mdash; NICE!
  6141.  
  6142. 10944 UVA (4)
  6143.  
  6144. 10818 UVA (5) //Easy &mdash; but not-easy implementation: ++Dijkstra [LEX!]
  6145.  
  6146. http://www.spoj.com/problems/A_W_S_N/ (4) //BFS + TSP (path) &mdash; NICE
  6147.  
  6148. </spoiler>
  6149.  
  6150. <spoiler summary="two-pointers">
  6151.  
  6152. http://www.spoj.com/problems/ADAFENCE/ [Multiple Pointers]
  6153.  
  6154. http://www.spoj.com/problems/ADAPLANT/
  6155.  
  6156. https://codeforces.com/contest/1166/problem/C (4) //[CONDITION][OBSERVATION]
  6157.  
  6158. https://codeforces.com/contest/1148/problem/B (4) //[NICE][BS]
  6159.  
  6160. https://codeforces.com/contest/1175/problem/C (4) //[NICE][GREEDY]
  6161.  
  6162. https://codeforces.com/contest/1203/problem/D1 (4) //[VERY NICE][STRINGS][PREPROCESS]
  6163.  
  6164. https://codeforces.com/contest/1203/problem/D2 (5) //[VERY NICE][STRINGS][PREPROCESS]
  6165.  
  6166. https://codeforces.com/contest/1186/problem/C (4) //[VERY NICE][BITS][OBSERVATION]
  6167.  
  6168. https://www.spoj.com/problems/MOZHCAN/ (5) //[VERY NICE]
  6169.  
  6170. http://codeforces.com/gym/101864 [L] (4) //Static Size [SORTING]
  6171.  
  6172. Dev Skills-499: Closest Pair Point (4) //[NICE][GEOMETRY][STRUCTURES]
  6173.  
  6174. http://codeforces.com/contest/919/problem/C (3) //Similar - simple sweep [EASY]
  6175.  
  6176. http://codeforces.com/contest/144/problem/C (3) //[NICE][FREQUENCY][STRINGS]
  6177.  
  6178. http://codeforces.com/contest/895/problem/B (3) //[OR BS]
  6179.  
  6180. http://codeforces.com/contest/84/problem/B (2) //EASY //ll
  6181.  
  6182. http://codeforces.com/contest/79/problem/C (4) //NICE - [STRINGS][SET][COMPARE]
  6183.  
  6184. http://codeforces.com/contest/746/problem/F 6
  6185.  
  6186. 11436 UVA (5)
  6187.  
  6188. http://codeforces.com/contest/760/problem/D 4
  6189.  
  6190. 11386 UVA (4)
  6191.  
  6192. http://www.spoj.com/problems/WOWSUBSTR2/ 3
  6193.  
  6194. http://www.spoj.com/problems/ARRAYSUB/ 4
  6195.  
  6196. http://www.spoj.com/problems/CODFURY/ 3 //easy &mdash; ukazkove
  6197.  
  6198. http://codeforces.com/contest/769/problem/B 3 //sort + TP
  6199.  
  6200. http://codeforces.com/contest/814/problem/C 4 //NICE &mdash; maybe some DP +/-
  6201.  
  6202. http://www.spoj.com/problems/CRAN04/ 4 //NICE &mdash; (more or less) 3 pointers
  6203.  
  6204. http://www.spoj.com/problems/OPCPIZZA/ 3 //NICE [EASY] [AGAINS EACH OTHER]
  6205.  
  6206. http://www.spoj.com/problems/ALIEN/ (3) //Classical
  6207.  
  6208. http://www.spoj.com/problems/HOTELS/ (3) //Classical & Easy
  6209.  
  6210. http://www.spoj.com/problems/KOIREP/ (4) //VERY NICE &mdash; N buckedt find mid diff
  6211.  
  6212. http://codeforces.com/contest/6/problem/E (4) //NICE &mdash; Multiset
  6213.  
  6214. http://codeforces.com/contest/873/problem/C (3) //NICE &mdash; M times 2P tenchique
  6215.  
  6216. </spoiler>
  6217.  
  6218. <spoiler summary="wavelet_tree">
  6219.  
  6220. UVA 1480
  6221.  
  6222. http://www.spoj.com/problems/ILKQUERY/
  6223.  
  6224. http://codeforces.com/contest/840/problem/D //Proposed by [user:GreenGrape]
  6225.  
  6226. </spoiler>
  6227.  
  6228. <spoiler summary="Zfunction">
  6229.  
  6230. https://www.codechef.com/problems/CHSTR //Proposed by [user:Apptica]
  6231.  
  6232. http://www.spoj.com/problems/SUFEQPRE/
  6233.  
  6234. http://codeforces.com/problemset/problem/126/B
  6235.  
  6236. http://codeforces.com/contest/119/problem/D (7) //[VERY NICE]
  6237.  
  6238. </spoiler>
  6239.  
  6240. <spoiler summary="2SAT">
  6241.  
  6242. https://www.urionlinejudge.com.br/judge/en/problems/view/1348 (4) //[CLASSICAL][NICE][SCC]
  6243.  
  6244. 11930 UVA (4)
  6245.  
  6246. http://codeforces.com/contest/776/problem/D (5)
  6247.  
  6248. </spoiler>
  6249.  
  6250. Finally if you would like to add some problem to the list &mdash; even though I would be glad, please do so only in case of:
  6251.  
  6252. 1. It is very interesting
  6253.  
  6254. 2. There is nothing, or low number of problems in the topic
  6255.  
  6256. 3. You add it in "bigger amount" at once
  6257.  
  6258. Thank you.
  6259.  
  6260. Offcourse if you have any remarks, questionns or requests, don't hesitate to ask.
  6261.  
  6262. PS: I'm sorry but there might be some duplicities. In that case, either report it or ignore it (unless they are in different topics, then it have reason :) )
  6263.  
  6264. Good Luck & Have Nice Day
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