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 ll long long
#define ld long double
#define pi 3.14159265359
int main(){
    string S; cin >> S;
    int N = S.size();
    vector<char> S1((N - 1) / 2), S2((N - 1) / 2), copyS1((N - 1) / 2), copyS2((N - 1) / 2);
    for (int i = 0; i < (N - 1) / 2; i++) {
        S1.at(i) = S.at(i);
        S2.at(i) = S.at(i + (N + 1) / 2);
        copyS1.at(i) = S.at(i);
        copyS2.at(i) = S.at(i + (N + 1) / 2);
    }
    string copyS = S;
    reverse(copyS.begin(), copyS.end());
    reverse(copyS1.begin(), copyS1.end());
    reverse(copyS2.begin(), copyS2.end());
    string ans = "Yes";
   if (S1 != copyS1 || S2 != copyS2 || S != copyS) {
       ans = "No";
   }
    cout << ans << endl;
}