func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     long long int t;     cin >> t;     while (t--) {       long long int n, cnt = 0;       cin >> n;       string s[n];       long long int h1[10] = {}, h2[10] = {};       for (int i = 0; i < n; i++) {         cin >> s[i];         h1[s[i][3] -  0 ]++;       }       for (int i = 0; i < n - 1; i++) {         for (int j = i + 1; j < n; j++) {           if (s[i].compare(s[j]) == 0) {             int k;             cnt++;             for (k = 0; k < 10; k++) {               if (h1[k] == 0) {                 break;               }             }             h1[s[i][3] -  0 ]--;             h1[k]++;             s[i][3] = k +  0 ;           }         }       }       cout << cnt << endl;       for (int i = 0; i < n; i++) {         cout << s[i] << endl;       }     }     return 0;   }   