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: Wrong Answer)

#include <bits/stdc++.h> 
using namespace std; 
#define ll int long long
int pa(string s)
{
    ll n=s.size();
    if(n==1)
    return true;
    if(n==2&&s[0]==s[1])
    return true;
    ll i=0;
    while(n>2)
    {
        if(s[i]==s[n-i-1])
        i++;
        else
        break;
        if(i==n-i-1)
        {
            
            return true;
        }
    }
    return false;
}

int main()
{
    string s;
    cin>>s;
    ll n=s.size();
   
    string s1 = s.substr(0,(n-1)/2);
 
    
    string s2=s.substr((n+1)/2,(n-1)/2);
   
    if(pa(s)&&pa(s1)&&pa(s2))
    cout<<"Yes"<<endl;
    else
    cout<<"No"<<endl;
    
}