#include <bits/stdc++.h>   using namespace std;   const int N = 4000 + 1;   const int sq = 100;   const long long int mod = 1e9 + 7;   const long long int inf = 4000 + 1;   unordered_map<long long int, int> dp;   int ps[N], n;   inline int get(int l, int r) { return ps[r] - ps[l]; }   int solve(int l, int r, int k, bool bol) {     if (r - l < k || l >= r || r > n || l < 0) return 0;     if (r - l == k && bol) return get(l, r);     if (r - l == k) return -get(l, r);     long long int key = l * N * sq * 2 + r * sq * 2 + k * 2 + bol;     if (dp.count(key)) return dp[key];     int ans, x, y;     if (bol) {       x = solve(l + k, r, k, 0) + get(l, l + k);       y = solve(l + k + 1, r, k + 1, 0) + get(l, l + k + 1);       ans = max(x, y);     } else {       x = solve(l, r - k, k, 1) - get(r - k, r);       y = solve(l, r - k - 1, k + 1, 1) - get(r - k - 1, r);       ans = min(x, y);     }     return dp[key] = ans;   }   int main() {     ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);     dp.rehash(16e6);     scanf( %d , &n);     for (int i = 0; i < n; i++) {       int x;       scanf( %d , &x);       ps[i + 1] = ps[i] + x;     }     printf( %d  n , solve(0, n, 1, 1));     return 0;   }   