func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     string s;     cin >> s;     int n = s.length();     vector<vector<int> > pos( z  -  a  + 1);     for (int i = 0; i < n; i++) pos[s[i] -  a ].push_back(i);     int good = 0;     for (int c = 0; c <=  z  -  a ; c++) {       if (pos[c].empty()) continue;       int c_good = 0;       for (int k = 0; k < n; k++) {         int cnt[ z  -  a  + 1] = {};         for (int i : pos[c]) cnt[s[(i + k) % n] -  a ]++;         int cur_c_good = 0;         for (int d = 0; d <=  z  -  a ; d++) cur_c_good += (cnt[d] == 1);         c_good = max(c_good, cur_c_good);       }       good += c_good;     }     cout.precision(10);     cout << fixed;     cout << (double)good / n;     return 0;   }   