func_code_string: #include <bits/stdc++.h>   using namespace std;   const double PI = acos(-1);   const double EPS = 1e-7;   const int inf = 1e8;   int main() {     int n, sum = 0;     cin >> n;     vector<int> in(n);     for (int i = 0; i < n; i++) cin >> in[i];     for (int i = 0; i < n; i++) sum += in[i];     vector<int> used(n);     for (int i = 0; i < n; i++)       if (!used[i]) {         for (int j = i + 1; j < n; j++)           if (!used[j] && in[i] + in[j] == sum * 2 / n) {             used[i] = used[j] = true;             cout << i + 1 <<     << j + 1 << endl;             break;           }       }   }   