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 9.2.1) (judge verdict: Wrong Answer)

#include<bits/stdc++.h>
using namespace std;
int main()
{
  string s;
  cin>>s;
  int len=s.size();
  int len1=len-1;
  int flag=0,flag1=0;
  int j=((len+3)/2)-1;
  for(int k=0;k<len;k++)
  {
      if(s[k]==s[len1])
      {
          flag=0;
      }
      else
      {
          flag=1;
      }
      len1--;
  }
  for(int i=0;i<=((len-1)/2)-1;i++)
  {
     if(s[i]==s[j])
     {
         flag1=0;
     }
     else
     {
         flag1=1;
     }
     j++;

  }



  if(flag==0 && flag1==0)
  {
      cout<<"Yes";
  }
  else
  {
      cout<<"No";
  }
  return 0;


}