func_code_string: #include <bits/stdc++.h>   using namespace std;   int t, n, bt[1000001] = {}, ar[1000001] = {};   vector<int> v;   int main() {     ios ::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     cin >> t;     while (t--) {       cin >> n;       for (int i = 0; i < n; i++) {         cin >> ar[i];         ar[i] = i - ar[i];         bt[i] = 0;       }       int x = 0;       while (!bt[x]) {         v.push_back(x);         bt[x] = v.size();         x = ar[x];       }       cout << v.size() - bt[x] + 1 <<   n ;       for (int i = bt[x] - 1; i < v.size(); i++) {         cout << v[i] + 1;         if (i < v.size() - 1) {           cout <<    ;         }       }       cout <<   n ;       v.clear();     }     return 0;   }   