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>

int main()
{
	char a[99];
	int i,n;
	for(i = 0; ; i++)
	{
		scanf("%c", a + i);
		if(a[i] == 10) 
		{
			a[i] = 0;
			break;
		}
	}
	n = i;
	int flag = 1;
	for(i = 0; i < (n-1)*0.5;i++)
	{
		if(a[i] != a[n-i-1])
			flag = 0;
	}
	if(n%4 == 3)
	{
	for(i = 0; i < (n-3)*0.25;i++)
	{
		if(a[i] != a[(int) ((n-3)*0.5 - i)])
			flag = 0;
	}
	
	for(i = 0; i < (n-3)*0.25;i++)
	{
		if(a[(int)(i + (n+1)*0.5)] != a[n-i-1])
			flag = 0;
	}
	}
	else
	{
	for(i = 0; i < (n-3)*0.25;i++)
	{
		if(a[i] != a[(int) ((n-3)*0.5 - i)])
			flag = 0;
	}
	
	for(i = 0; i < (n-3)*0.25;i++)
	{
		if(a[(int) (i + (n+1)*0.5)] != a[n-i-1])
			flag = 0;
	}
	}
	
	
	if(flag)
	{
		printf("Yes");
	}
	else printf("No");
}