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<iostream>
#include<vector>
using namespace std;

int main(){
  string s;
  bool a=false,b=false,c=false;
  cin>>s;
  
  for(int i=0;i<s.size()/2;i++){
    if(s.at(i)==s.at(s.size()-i-1)){
      if(i==s.size()/2-1){a=true;}
    }
    else{break;}
  }
  
  for(int i=0;i<s.size()/4;i++){
    if(s.at(i)==s.at(s.size()/2-1-i)){
      if(i==s.size()/4-1){b=true;}
    }
    else{break;}
  }
  
  for(int i=0;i<s.size()/4;i++){
    if(s.at(s.size()/2+1+i)==s.at(s.size()-1-i)){
      if(i==s.size()/4-1){c=true;}
    }
    else{break;}
  }
  
  if(a&&b&&c){cout<<"Yes";}
  else{cout<<"No";}
}