func_code_string: #include <bits/stdc++.h>   using namespace std;   string s;   int yekdast(char c, int l, int r) {     int ans = 0;     for (int i = l; i <= r; i++) {       if (s[i] != c) ans++;     }     return ans;   }   int check(char c, int l, int r) {     if ((r - l) > 1) {       int mid1 = (floor((l * 1.0 + r * 1.0) / 2.0)),           mid2 = (ceil((l * 1.0 + r * 1.0) / 2.0));       int first = check(char(c + 1), l, mid1) + yekdast(c, mid2, r);       int second = check(char(c + 1), mid2, r) + yekdast(c, l, mid1);       return min(first, second);     } else if (r == l + 1) {       int first = check(char(c + 1), l, l) + yekdast(c, r, r);       int second = check(char(c + 1), r, r) + yekdast(c, l, l);       return min(first, second);     } else {       return yekdast(c, l, r);     }   }   int t, n;   int main() {     cin >> t;     for (int i = 0; i < t; i++) {       cin >> n >> s;       cout << check( a , 0, n - 1) << endl;     }   }   