func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       int len, k;       cin >> len >> k;       string s;       cin >> s;       sort(s.begin(), s.end());       if (s[0] != s[k - 1])         cout << s[k - 1] << endl;       else {         cout << s[k - 1];         if (s[k] == s[len - 1]) {           int q = (len - k) / k;           if ((len - k) % k) q++;           while (q--) cout << s[k];         } else           for (int i = k; i < len; i++) cout << s[i];         cout << endl;       }     }     return 0;   }   