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"
using namespace std;
// #define endl '\n'
// #define int long long

signed main() {

	string s;
	cin >> s;
	
	
	int n = s.size();
	s = ' ' + s;
	
	for (int i=1, j=n; i<j; i++, j--) {
		if (s[i] != s[j]) {
			cout << "No" << endl;
			exit(0);
		}
	}
	
	for (int i=1, j=(n-1)/2; i<j; i++, j--) {
		if (s[i] != s[j]) {
			cout << "No" << endl;
			exit(0);
		}
	}
	
	for (int i=(n+3)/2, j=n; i<j; i++, j--) {
		if (s[i] != s[j]) {
			cout << "No" << endl;
			exit(0);
		}
	}
	
	cout << "Yes" << endl;
	
}