func_code_string: #include <bits/stdc++.h>   using namespace std;   template <class L, class R>   ostream& operator<<(ostream& os, pair<L, R> P) {     return os <<  (  << P.first <<  ,  << P.second <<  ) ;   }   template <class T>   ostream& operator<<(ostream& os, vector<T> V) {     os <<  [  ;     for (auto v : V) os << v <<    ;     return os <<  ] ;   }   template <class T>   ostream& operator<<(ostream& os, set<T> second) {     os <<  {  ;     for (auto s : second) os << s <<    ;     return os <<  } ;   }   template <class L, class R>   ostream& operator<<(ostream& os, map<L, R> M) {     os <<  {  ;     for (auto m : M) os <<  (  << m.first <<   :   << m.second <<  )  ;     return os <<  } ;   }   template <typename Arg1>   void __f(const char* name, Arg1&& arg1) {     cout << name <<   :   << arg1 <<   n ;   }   template <typename Arg1, typename... Args>   void __f(const char* names, Arg1&& arg1, Args&&... args) {     const char* comma = strchr(names + 1,  , );     cout.write(names, comma - names) <<   :   << arg1 <<   | ;     __f(comma + 1, args...);   }   void solve() {     map<int, int> cnt;     int n;     cin >> n;     for (int i = 0; i < n; ++i) {       int x;       cin >> x;       cnt[x]++;     }     int a = -1;     for (int i = 0; i <= 101; ++i) {       if (cnt[i] == 0) {         cout << i + (a == -1 ? i : a) <<   n ;         return;       } else if (cnt[i] == 1 and a == -1) {         a = i;       }     }   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     int T = 1, tc = 1;     cin >> T;     while (T--) {       solve();     }     return 0;   }   