func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 5005;   const int maxm = maxn * 2;   const int maxe = 200005;   const int mod = 1e9 + 7;   int n, a, b;   string str;   int cc[26][maxn][26];   int exist[26];   int main() {     cin >> str;     n = str.length();     for (int i = 0; i < n; i++) {       int idx = str[i] -  a ;       exist[idx]++;       for (int j = 1; j < n; j++) {         int pos = (i + j) % n;         int idx2 = str[pos] -  a ;         cc[idx][j][idx2]++;       }     }     double ans = 0;     for (int i = 0; i < 26; i++) {       double cccc = 0;       for (int j = 1; j < n; j++) {         double tp = 0;         for (int ii = 0; ii <= n; ii++) {           if (str[ii] -  a  != i) continue;           int pos = (ii + j) % n;           int idx2 = str[pos] -  a ;           if (cc[i][j][idx2] == 1) tp++;         }         cccc = max(cccc, tp);       }       ans += cccc;     }     printf( %.15lf n , ans / n);     return 0;   }   