func_code_string: #include <bits/stdc++.h>   int main() {     int q;     std::cin >> q;     while (q--) {       int n, ans(0);       std::cin >> n;       std::set<std::string> check, p;       std::string s;       std::vector<std::string> res, a(n);       for (int i = 0; i < n; i++) {         std::cin >> a[i];         check.insert(a[i]);       }       for (int i = 0; i < n; i++) {         if (p.find(a[i]) != p.end()) {           std::string t = a[i];           for (int x = 0; x < 10; x++) {             if (check.find(t) == check.end()) {               check.insert(t);               p.insert(t);               break;             }             t[0] = char( 0  + x);           }           ++ans;           res.push_back(t);         } else {           res.push_back(a[i]);           p.insert(a[i]);         }       }       std::cout << ans << std::endl;       for (int i = 0; i < res.size(); i++) {         std::cout << res[i] << std::endl;       }     }     return 0;   }   