func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       int arr[105];       for (int i = 0; i < n; i++) {         cin >> arr[i];       }       int visited[105] = {0};       for (int i = 0; i < n; i++) {         visited[arr[i]]++;       }       int flag1 = -1;       int flag2 = -1;       for (int i = 0; i < 105; i++) {         if (visited[i] == 1 and flag1 == -1) {           flag1 = i;         }         if (visited[i] == 0 and flag1 == -1) {           flag1 = i;           flag2 = i;           break;         } else if (visited[i] == 0 and flag1 != -1) {           flag2 = i;           break;         }       }       cout << flag1 + flag2 << endl;     }   }   