func_code_string: #include <bits/stdc++.h>   using namespace std;   const int Maxn = 500005;   int n;   int a[Maxn];   long long L[Maxn], R[Maxn];   int delt[Maxn];   long long res;   int main() {     scanf( %d , &n);     for (int i = 1; i <= n; i++) {       scanf( %d , &a[i]);       L[i] = L[i - 1] + a[i];     }     if (L[n] % 3)       printf( 0 n );     else {       long long need = L[n] / 3;       for (int i = n; i >= 1; i--) {         R[i] = R[i + 1] + a[i];         delt[i] = delt[i + 1] + (R[i] == need);       }       for (int i = 1; i <= n; i++)         if (L[i] == need) res += delt[i + 2];       printf( %I64d n , res);     }     return 0;   }   