func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     ;     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       vector<int> arr(n);       map<int, int> mp;       for (int i = 0; i < n; i++) {         cin >> arr[i];         mp[arr[i]]++;       }       int ans = 0;       int ct = 0;       for (int i = 0; i <= 100; i++) {         if (ct < 2) {           if (mp[i] == 0) {             ans += (2 - ct) * i;             if (ct == 1)               ct++;             else               ct += 2;           } else if (mp[i] % 2 == 0)             continue;           else if (mp[i] == 1) {             if (ct == 1)               continue;             else {               ct++;               ans += i;             }           }         } else           break;       }       cout << ans << endl;     }   }   