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;
int main()
{
    int n,i,j,flag=0,k,flag1=0,flag2=0;
    string s;
    cin>>s;
    n=s.length();
    for(i=0;i<n/2;i++)
    {
        if(s[i]!=s[n-1-i])
        {
            flag=1;
            break;
        }
    }
    if(flag==1)
       cout<<"No";
    else
    {
        for(j=0;j<(n-1)/4;j++)
        {
            if(s[j]!=s[((n-1)/2)-1-j])
            {
                flag1=1;
                break;
            }
        }
        for(k=((n+3)/2)-1;k<n/2;k++)
        {
            if(s[k]!=s[n-1-k])
            {
                flag2=1;
                break;
            }
        }
        if(flag1==0&&flag2==0)
            cout<<"Yes";
        else
            cout<<"No";
    }

}