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 5.4.1) (judge verdict: Accepted)

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

int kaibun(char *s){
    int len=strlen(s);
    char t[len+1];
    strcpy(t,s);
    int i,j;
    char tmp;
    for(i=0,j=len-1;i<len/2;i++,j--){
        tmp=t[i];
        t[i]=t[j];
        t[j]=tmp;
    }
    return strcmp(s,t);
}

int main(void)
{
    char s[100]={};
    char t[100]={};
    char u[100]={};
    scanf("%s",&s);
    int len=strlen(s);
    strncpy(t,s,(len-1)/2);
    strncpy(u,&s[(len+1)/2],(len-1)/2);
    if(kaibun(s)){
        printf("No");
    }else if(kaibun(t)){
        printf("No");
    }else if(kaibun(u)){
        printf("No");
    }else{
        printf("Yes");
    }

    return 0;
}