func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       std::vector<pair<long long int, long long int> > ev;       std::vector<pair<long long int, long long int> > od;       for (int i = 1; i <= 2 * n; i++) {         int x;         cin >> x;         if (x % 2 == 0)           ev.push_back({x, i});         else           od.push_back({x, i});       }       if (ev.size() % 2 == 0) {         if (ev.size() == 0) {           od.pop_back();           od.pop_back();         } else {           ev.pop_back();           ev.pop_back();         }       } else {         ev.pop_back();         od.pop_back();       }       for (int i = 0; i < ev.size(); i += 2)         cout << ev[i].second <<     << ev[i + 1].second <<   n ;       for (int i = 0; i < od.size(); i += 2)         cout << od[i].second <<     << od[i + 1].second <<   n ;     }     return 0;   }   