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>
#include<math.h>
typedef long long ll;

int palin(const char *s)
{
    int l=strlen(s);
    char t[l+1];
    for(int i=0;i<l;i++)
    {
        t[i]=s[l-i-1];
    }
    t[l]='\0';
    if(strcmp(s,t)==0)
    {
        return 0;
    }
    else
    {
        return 1;
    }
    
}


int main()
{

    char s[100];
    scanf("%s",s);
    int flag;

    flag=palin(s);

    if(flag!=0)
    {
        printf("No\n");
    }
    else
    {
        int n=strlen(s);
        char t[((n-1)/2)+1];
        for(int i=0;i<(strlen(s)-1)/2;i++)
        {
            t[i]=s[i];
        }
        t[sizeof(t)-1]='\0';

        flag=palin(t);
        
        if(flag==0)
        {
            printf("Yes\n");
        }
        else
        {
            printf("No\n");
        }
    }
    return 0;
}