func_code_string: #include <bits/stdc++.h>   using namespace std;   void solve() {     int n;     cin >> n;     vector<long long> a(n + 1, 0);     long long s1 = 0, s2 = 0, s3 = 0;     for (int i = 1; i <= n; i++) {       scanf( %lld , &a[i]);       a[i] += a[i - 1];     }     if (a[n] % 3) {       cout <<  0 n ;       return;     }     vector<int> a0, a1;     for (int i = 1; i < n; i++) {       if (a[i] == a[n] / 3) a0.push_back(i);       if (a[i] == 2 * a[n] / 3) a1.push_back(i);     }     long long ret = 0;     while (a0.size() && a1.size()) {       while (a0.size() && a0.back() >= a1.back()) {         a0.pop_back();       }       if (!a0.size()) break;       ret += a0.size();       a1.pop_back();     }     cout << ret << endl;   }   int main() {     solve();     return 0;   }   