func_code_string: #include <bits/stdc++.h>   using namespace std;   const long double EPS = (long double)1e-7;   const long double PI = acos(0) * 2;   bool isZero(const long double& x) { return abs(x) <= EPS; }   int sign(const long double& x) { return isZero(x) ? 0 : (0 < x ? 1 : -1); }   long long gcd(long long a, long long b) {     for (; b; a %= b, swap(a, b)) {     }     return abs(a);   }   pair<long long, long long> operator+(const pair<long long, long long>& a,                                        const pair<long long, long long>& b) {     return pair<long long, long long>(a.first + b.first, a.second + b.second);   }   pair<long long, long long> operator-(const pair<long long, long long>& a,                                        const pair<long long, long long>& b) {     return pair<long long, long long>(a.first - b.first, a.second - b.second);   }   pair<long long, long long> operator*(const pair<long long, long long>& a,                                        const long long& b) {     return pair<long long, long long>(a.first * b, a.second * b);   }   long long operator*(const pair<long long, long long>& a,                       const pair<long long, long long>& b) {     return a.first * b.second - b.first * a.second;   }   long long ccw(const pair<long long, long long>& a,                 const pair<long long, long long>& b,                 const pair<long long, long long>& c) {     return a * b + b * c + c * a;   }   void fg(vector<int> G[], int a, int b) {     G[a].emplace_back(b);     G[b].emplace_back(a);   }   void fg(vector<pair<int, int> > G[], int a, int b, int c) {     G[a].emplace_back(b, c);     G[b].emplace_back(a, c);   }   const int MAXN = 1000055;   int A[MAXN], B[MAXN];   bitset<MAXN> C;   int T, N;   void run() {     cin >> N;     for (int i = 1; i <= N; i++) {       cin >> A[i];       B[i] = i - A[i];     }     vector<int> V;     for (int i = 1;;) {       V.emplace_back(i);       if (C[i]) break;       C[i] = true;       i = B[i];     }     for (int v : V) C[v] = false;     V.erase(V.begin(), find(((V).begin()), ((V).end()), V.back()) + 1);     cout << ((int)(V).size()) <<   n ;     for (int v : V) cout << v <<    ;     cout <<   n ;   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     for (cin >> T; T--;) run();     return 0;   }   