func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       vector<int> a(2 * n);       for (auto &it : a) cin >> it;       vector<int> kop(n);       vector<int> ARR;       for (int i = 0; i < 2 * n; ++i) {         if (!kop[a[i] - 1]) {           kop[a[i] - 1] = true;           ARR.push_back(a[i]);         }       }       for (auto it : ARR) cout << it <<    ;       cout << endl;     }     return 0;   }   