Problem:
Score : 200 points

Problem Statement

A string S of an odd length is said to be a strong palindrome if and only if all of the following conditions are satisfied:

S is a palindrome.

Let N be the length of S. The string formed by the 1-st through ((N-1)/2)-th characters of S is a palindrome.

The string consisting of the (N+3)/2-st through N-th characters of S is a palindrome.

Determine whether S is a strong palindrome.

Constraints

S consists of lowercase English letters.

The length of S is an odd number between 3 and 99 (inclusive).

Input

Input is given from Standard Input in the following format:

S

Output

If S is a strong palindrome, print Yes;
otherwise, print No.

Sample Input 1

akasaka

Sample Output 1

Yes

S is akasaka.

The string formed by the 1-st through the 3-rd characters is aka.

The string formed by the 5-th through the 7-th characters is aka.
All of these are palindromes, so S is a strong palindrome.

Sample Input 2

level

Sample Output 2

No

Sample Input 3

atcoder

Sample Output 3

No

Solution in C (GCC 9.2.1) (judge verdict: Accepted)

#include <stdio.h>
#include <string.h>

int f(char *S,int N){
  for(int i=0;i<N/2;i++){
    if(S[i]!=S[N-1-i]) return 0;
  }
  return 1;
}

int main(){
  char S[101],T[101],U[101];
  int N;
  scanf("%s",S);
  N=strlen(S);
  for(int i=0;i<(N-1)/2;i++) T[i]=S[i];
  for(int i=(N+3)/2-1;i<N;i++) U[i-(N+3)/2+1]=S[i];
  if(f(S,N)*f(T,(N-1)/2)*f(U,(N-1)/2)==1) printf("Yes\n");
  else printf("No\n");
  return 0;
}