Use stl in some code___force problem;

 1.VECTOR : https://codeforces.com/problemset/problem/1108/B
note : 2 divisor;


2 -Map :  https://codeforces.com/contest/672/problem/B


3- (Set + ARRAY)  : https://codeforces.com/contest/1238/problem/B


4 - Esay Map : https://codeforces.com/contest/459/problem/B

5 - (Vector +Pair +Sort) : https://codeforces.com/problemset/problem/16/B

note: vector k reverse sort korta hoba ,like that - sort(v.rbegin(),v.rend());
      mona rakta hola pair_vector ka sort korra first value k key dora sort hoba ,,jodi amora second value  ar opor sort kori tahola
      sort ar sata alada compare funtion lakta hoba ,,,tai amora amon babAY input nibo jata first value opor sort korla code hoba;


6.STACK: https://codeforces.com/problemset/problem/26/B

note :  braket ar sob pb stack diha solve kora jaba ,,,,,,,


7. DEQUE : https://codeforces.com/contest/1234/problem/B1

NOTE : NEW OYLA PARTAI NAI BADDOW ,,,, TUMI ETA SOLVE KORAR PUHA OY NAI ,,, SHAKIB BHAI RA JIKOW;;;


8. MAP+VECTOR+ARRAY :https://codeforces.com/problemset/problem/978/A

9:VECTOR+ PAIR +min max deep basic:   https://codeforces.com/problemset/problem/1008/B

10:TWO pointer + MAP : https://codeforces.com/problemset/problem/1225/B2

NOTE: SAME counting bar bar na kora ekbar kora ,,,,ai count ka update kora ans bar korar try koro map use kora.


11:DEQUE : https://codeforces.com/contest/381/problem/A

NOTE: DEQUE ar loop while guranu lagba like  while(!dq.empty) nami

12 TWO POINTER: https://codeforces.com/problemset/problem/489/B

NOTE -:SORT KORTA HOBA POTAMA,,,,,, 2 LOOP NA USE KORA EK LOOP USE KORO ;


13 :https://codeforces.com/contest/1189/problem/B  ;


14 :EASY SET:https://codeforces.com/contest/44/problem/A  ;;;



15: not map not stl ,sometime use your brain::::::https://codeforces.com/contest/591/problem/B;

note : first take a string a to z; then change it you need ; final out put like that cout<<s[str[i]-'a'];



16 map same run_time : https://codeforces.com/contest/1277/problem/B

note : same thing ber ber na kora ,ekbar kora map use soro ;

boro taka chuto  ara ar sort------  sort(ara, ara+n, greater<int>());

17 two pointer : https://codeforces.com/contest/279/problem/B

note :sum one bar count kora tak sum + o - kora and cnt + - kora max bar koro ;;;;;;;

18 map+vector;https://codeforces.com/contest/1114/problem/B

note : 2ta vector noy and ek ta reverse sort kora  kora sum bar kora ,,,, number ta ka sort na kora position map ar help ar bar koro;;;;;;;


19 set + size : https://codeforces.com/problemset/problem/1228/A
note: str=to_string(i);


20 :2D VECTOR/ 2D ARRAY :https://codeforces.com/problemset/problem/1187/B ;



21 lexicographically minimal permutation: https://codeforces.com/problemset/problem/1315/C

note : maping or shashing;

22. stact sara amar cholai na:https://codeforces.com/problemset/problem/1104/B

note same to pb 6:::6.STACK


23 2D MAP/ PAIR MAP::  https://codeforces.com/problemset/problem/1296/C

nate: 1. map<pair<ll,ll>,ll>mp;  /// pair map
      2  mp[{0,0}]=0;              /// 0 0/pos zero kora
      3 mp.find({x,y})!=mp.end(); condition map a x,y asa ki na?



24 easy set: https://codeforces.com/problemset/status
note :set a chuto taka boro sajanu taka;

25 two pointer :https://codeforces.com/contest/6/problem/C