func_code_string: #include <bits/stdc++.h>   using namespace std;   int lowbit(int a) { return a & (-a); }   int getans(char c, int l, int r, string &s) {     if (l == r) {       return s[l] != c;     }     int len = r - l + 1;     int cnt = 0;     for (int i = l; i < l + len / 2; i++) {       if (s[i] != c) cnt++;     }     int ans = cnt + getans(c + 1, l + len / 2, r, s);     cnt = 0;     for (int i = l + len / 2; i <= r; i++) {       if (s[i] != c) cnt++;     }     ans = min(ans, cnt + getans(c + 1, l, l + len / 2 - 1, s));     return ans;   }   int main() {     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       string s;       cin >> s;       cout << getans( a , 0, n - 1, s) <<   n ;     }   }   