func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long mod = 1e9 + 7;   const long long inf = 1e9;   const long long N = 1000 + 5;   long long ar[N], done[N], cnt[N];   long long n;   long long mex() {     for (long long i = 0; i < n; i++) cnt[i] = 0;     for (long long i = 0; i < n; i++) cnt[ar[i]] = 1;     long long mex = 0;     while (cnt[mex]) mex++;     return mex;   }   int32_t main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     long long t = 1;     cin >> t;     while (t--) {       cin >> n;       for (long long i = 0; i < n; i++) {         cin >> ar[i];       }       vector<long long> ans;       while (1) {         long long m = mex();         if (m < n) {           ar[m] = m;           ans.push_back(m + 1);         } else {           long long ind = 0;           while (ind < n && ar[ind] == ind) ind++;           if (ind == n) break;           long long p = -1;           for (long long i = 0; i < n && p == -1; i++)             if (ar[i] == ind) p = i;           ar[p] = n;           ans.push_back(p + 1);         }       }       cout << ans.size() <<   n ;       for (auto &inx : ans) cout << inx <<    ;       cout <<   n ;     }   }   