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<stdio.h>
#include<iostream>
#include<math.h>
using namespace std;
int main(void){
    int S[99],N,i,m,l,n,flag=1;
    
    for(i = 0;;i++){
        S[i] = getchar();
        N = i;
        if(S[i] == '\n')
            break;
        
    }
    m = (N-1)/2-1;
    l = (N+3)/2-1;
    n=N-1;
    
    for(i = 0;i < (N-1)/2;i++,m--){
        if(S[i] != S[m]){
            flag = 0;
        }
    }
    for(i = N;i > (N+3)/2;i--,l++,n--){
        if(S[l] != S[n]){
            flag = 0;
        }
    }
    if(flag == 0)
        printf("No\n");
    else
        printf("Yes\n");
        
    return 0;
}