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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<bits/stdc++.h>
using namespace std;

#define ll long long int
int main() 
{

ll i,j,n,m;
string a;
cin>>a;
n=a.size();
m=(n-1)/2;
int k=(n+3)/2;
int f=0;
for(i=0;i<n/2;i++)
{
	if(a[i]!=a[n-1-i])
	{
		f=1;break;
	}
}
for(i=0;i<m;i++)
{

	if(a[i]!=a[m-1-i])
	{
		f=1;break;
	}
}
for(i=k-1;i<n;i++)
{

	if(a[i]!=a[n-1-i])
	{
		f=1;break;
	}
}
if(f==0)
	cout<<"Yes"<<endl;
else
	cout<<"No"<<endl;
}