func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MSIZE = 1e3 + 5;   const int MOD = 1e9 + 7;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int t;     cin >> t;     while (t--) {       int n, k;       cin >> n >> k;       string s;       cin >> s;       int cnt[26] = {0};       for (char c : s) cnt[c -  a ]++;       int os = 0;       for (int i = 0; i <= 25; i++) {         if (cnt[i] >= k - os) {           cnt[i] -= (k - os);           cout << (char)( a  + i);           break;         }         os += cnt[i];         cnt[i] = 0;       }       if (os) {         cout << endl;         continue;       }       bool pr = 0;       for (int i = 0; i <= 25; i++) {         if (cnt[i] and cnt[i] == n - k) {           int val = cnt[i] / k + (cnt[i] % k != 0);           while (val--) cout << (char)( a  + i);           break;         }         while (cnt[i]--) cout << (char)( a  + i);       }       cout << endl;     }     return 0;   }   