func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     long long i, j, k;     int n;     cin >> n;     vector<long long> arr(n);     long long sum = 0;     for (i = 0; i < n; i++) {       cin >> arr[i];       sum += arr[i];     }     if (sum % 3 != 0) {       cout << 0 << endl;       return 0;     }     if (n < 3) {       cout << 0 << endl;       return 0;     }     long long s = sum / 3;     vector<int> ans(n, 0);     long long pref = 0;     for (i = n - 1; i >= 0; i--) {       pref += arr[i];       if (pref == s) {         ans[i] = 1;       }     }     for (i = n - 2; i >= 0; i--) {       ans[i] += ans[i + 1];     }     pref = 0;     long long soln = 0;     for (i = 0; i < n - 2; i++) {       pref += arr[i];       if (pref == s) {         soln += ans[i + 2];       }     }     cout << soln << endl;     return 0;   }   