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>
#define LL long long
#define mp make_pair
#define pb push_back
#define VI vector<int>
#define pii pair<int,int>
using namespace std;
char S[110];
int n;
bool pal(int x, int y){
	for(int i = x, j = y; i <= j; i++, j--){
		if(S[i] != S[j]) return false;
	}
	return true;
}
int main(){
	scanf("%s", S);
	n = strlen(S);
	printf("%s\n", (pal(0, n-1) && pal(0,n/2-1) && pal(n/2+1, n-1)) ? "Yes" : "No");
	return 0;
}