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El_GEMMY

removal game

Dec 1st, 2022
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C++ 3.68 KB | None | 0 0
  1. // Those who cannot remember the past are
  2. // condemned to repeat it (use DP -_-)
  3. // - George Santayana
  4.  
  5. #include <bits/stdc++.h>
  6. #include <ext/pb_ds/assoc_container.hpp>
  7. #include <ext/pb_ds/tree_policy.hpp>
  8.  
  9. using namespace std;
  10. using namespace __gnu_pbds;
  11.  
  12. #define all(v) v.begin(), v.end()
  13. #define rall(v) v.rbegin(), v.rend()
  14. #define ll long long
  15. #define ull unsigned long long
  16. #define MOD 1000000007
  17. #define PI acos(-1)
  18. #define ceil(a, b) (((a) / (b)) + ((a) % (b) ? 1 : 0))
  19. #define imin INT_MIN
  20. #define imax INT_MAX
  21. #define llmax LLONG_MAX
  22. #define llmin LLONG_MIN
  23. #define inf 2000000000
  24. #define nl '\n'
  25. #define ppcnt __builtin_popcount
  26. #define ppcntll __builtin_popcountll
  27. #define clz __builtin_clz
  28. #define clzll __builtin_clzll
  29. #define ctz __builtin_ctz
  30. #define ctzll __builtin_ctzll
  31. #define modulo(a, b, mod) ((((a) % (mod)) + ((b) % (mod))) % (mod))
  32. #define cnte(v, x) count(all(v), (x))
  33. #define mine(v) min_element(all(v))
  34. #define maxe(v) max_element(all(v))
  35. #define updmin(a, b) a = min(a, b)
  36. #define updmax(a, b) a = max(a, b)
  37. #define findmod(x, m) x = ((x) % (m) + (m)) % m
  38. #define getmod(x, m) ((x) % (m) + (m)) % (m)
  39. #define debug(x) cout << "x: " << (x) << nl;
  40. #define debug2(x, y) cout << "x: " << (x) << " y: " << y << nl;
  41. #define ordered_set tree<pair<int, int>, null_type, less<>, rb_tree_tag, tree_order_statistics_int_update>
  42. #define ordered_map tree<int, int, less<>, rb_tree_tag, tree_order_statistics_int_update>
  43.  
  44. //vector<int> dx = {0, 0, 1, -1, 1, 1, -1, -1}, dy = {1, -1, 0, 0, 1, -1, 1, -1};
  45. //vector<int> dx = {0, 0, 1, -1}, dy = {1, -1, 0, 0};
  46. //vector<int> dx = {2, 1, -1, -2, -2, -1, 1, 2}, dy = {1, 2, 2, 1, -1, -2, -2, -1};
  47.  
  48. template<typename T = int>
  49. istream &operator>>(istream &in, vector<pair<int, int>> &v) {
  50.     for (auto &[x, y]: v) in >> x >> y;
  51.     return in;
  52. }
  53.  
  54. template<typename T = int>
  55. istream &operator>>(istream &in, vector<T> &v) {
  56.     for (T &i: v) in >> i;
  57.     return in;
  58. }
  59.  
  60. template<typename T = int>
  61. ostream &operator<<(ostream &out, const vector<T> &v) {
  62.     for (const T &x: v)
  63.         out << x << ' ';
  64.     return out;
  65. }
  66.  
  67. template<typename T = pair<int, int>>
  68. ostream &operator<<(ostream &out, const vector<pair<int, int>> &v) {
  69.     for (auto &[x, y]: v) {
  70.         out << x << ' ' << y << nl;
  71.     }
  72.     return out;
  73. }
  74.  
  75. void Start_Crushing() {
  76.     ios_base::sync_with_stdio(false);
  77.     cin.tie(nullptr);
  78.     cout.tie(nullptr);
  79. #ifndef ONLINE_JUDGE
  80.     freopen("input.txt", "r", stdin);
  81.     freopen("output.txt", "w", stdout);
  82. #endif
  83. }
  84. int n;
  85. vector<int> v;
  86. vector<vector<ll>> memo;
  87.  
  88. ll dp(int turn, int l){
  89.     if(turn > n){
  90.         return 0;
  91.     }
  92.  
  93.     ll& ret = memo[turn][l];
  94.     if(~ret)
  95.         return ret;
  96.  
  97.     int r = n - (turn - l - 1) - 1;
  98.     ret = 0;
  99.  
  100.     if(turn & 1){
  101.         ret = max(v[l] + dp(turn + 1, l + 1), v[r] + dp(turn + 1, l));
  102.     }else{
  103.         ret = min(dp(turn + 1, l + 1), dp(turn + 1, l));
  104.     }
  105.  
  106.     return ret;
  107. }
  108.  
  109. void solve(){
  110.     cin >> n;
  111.     v.resize(n); cin >> v;
  112.     memo.assign(n + 1, vector<ll>(n + 1, -1));
  113.  
  114.     ll ans = dp(1, 0);
  115.  
  116.     cout << ans;
  117. }
  118.  
  119. void set_file(string &file_name) {
  120.     freopen((file_name + ".in").c_str(), "r", stdin);
  121.     freopen((file_name + ".out").c_str(), "w", stdout);
  122. }
  123.  
  124. int main() {
  125.     Start_Crushing();
  126.  
  127. //    string file_name = "knapsack";
  128. //    set_file(file_name);
  129.     int t = 1;
  130. //    /*Multiple test cases?*/ cin >> t;
  131.  
  132.     while (t--) {
  133.         solve();
  134.         if (!t)
  135.             break;
  136.         cout << nl;
  137.     }
  138.  
  139. //    for(int tc = 1; tc <= t; tc++){
  140. ////        cout << "Case " << tc << ": ";
  141. //        solve();
  142. //        if(tc != t)
  143. //            cout << nl;
  144. //    }
  145.  
  146.     return 0;
  147. }
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