func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 1005;   int a[maxn];   int ans[maxn << 1];   int vis1[maxn], vis[maxn];   int main() {     int T;     scanf( %d , &T);     while (T--) {       int n;       scanf( %d , &n);       int res = n;       int p = 0;       int mex;       for (int i = 1; i <= n; i++) {         scanf( %d , &a[i]);         vis1[i] = 0;       }       while (res > 0) {         for (int i = 0; i <= n; i++) vis[i] = 0;         for (int i = 1; i <= n; i++) vis[a[i]] = 1;         for (int i = 0;; i++) {           if (!vis[i]) {             mex = i;             break;           }         }         if (mex == 0) {           for (int i = 1; i <= n; i++) {             if (!vis1[i]) {               a[i] = mex;               ans[++p] = i;               break;             }           }         } else {           ans[++p] = mex;           a[mex] = mex;           vis1[mex] = 1;           res--;         }       }       printf( %d n , p);       for (int i = 1; i <= p; i++) printf( %d  , ans[i]);       printf(  n );     }     return 0;   }   