func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e5 + 5, INF = 1e9 + 7;   int n, a[N];   bool used[N];   int main() {     int q;     cin >> q;     while (q--) {       cin >> n;       for (int i = 1; i <= n * 2; i++) {         cin >> a[i];         used[i] = 0;       }       vector<pair<int, int> > vec;       for (int i = 1; i <= n * 2; i++) {         if (used[i]) continue;         for (int j = i + 1; j <= n * 2; j++) {           if ((a[i] + a[j]) % 2 == 0) {             used[j] = 1;             used[i] = 1;             vec.push_back({i, j});             break;           }         }       }       bool cond = 1;       for (int i = 1; i <= n * 2; i++) {         if (!used[i]) {           cond = 0;         }       }       for (int i = 0; i < vec.size() - cond; i++) {         cout << vec[i].first <<     << vec[i].second << endl;       }     }   }   