func_code_string: #include <bits/stdc++.h>   using namespace std;   const long double pi = 3.1415926535897932384626433832795l;   template <typename T>   inline auto sqr(T x) -> decltype(x * x) {     return x * x;   }   template <typename T1, typename T2>   inline bool umx(T1& a, T2 b) {     if (a < b) {       a = b;       return 1;     }     return 0;   }   template <typename T1, typename T2>   inline bool umn(T1& a, T2 b) {     if (b < a) {       a = b;       return 1;     }     return 0;   }   bool use[26];   int main() {     cout.setf(ios::showpoint | ios::fixed);     cout.precision(20);     string s;     getline(cin, s);     bool ok = 1;     for (int i = int(0); i < int(((int)(s).size())); ++i) {       int idx = s[i] -  a ;       if (idx > 0) {         if (!use[idx - 1]) {           ok = 0;         }       }       use[idx] = 1;     }     if (!ok) {       puts( NO );     } else {       puts( YES );     }     return 0;   }   