func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       string s(200,  a );       cout << s << endl;       for (int i = 0; i < n; i++) {         int u;         cin >> u;         s[u] = s[u] ==  a  ?  b  :  a ;         cout << s << endl;       }     }   }   