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 (Clang 3.8.0) (judge verdict: Wrong Answer)

#include <iostream>
#include <vector>
#include <algorithm>
#include <map>

#define rep(i, n) for(int i = 0; i < (int)n; i++)
#define reps(i, s, n) for(int i = (int)s; i < (int)n; i++)
#define in(i) std::cin >> i;
#define print(i) std::cout << i;
#define println(i) std::cout << i << std::endl;

bool palindrome(std::string str, int s, int end) {
    int t = (end - s)/2;
    int cnt = 1;
    bool flg = true;
    for(;;) {
        if((t-cnt >= s) && t + cnt <= end) {
            if(str[t-cnt] != str[t+cnt]) {
                flg = false;
                break;
            }
            cnt++;
        }
        else break;
    }
    if(flg)return true;
    else return false;
}

int main() {
    std::string s;
    in(s);
    if(palindrome(s, 0, s.length()-1) && palindrome(s, 0, (s.length()-2)/2) && palindrome(s, (s.length()+2)/2, s.length()-1))
        std::cout << "Yes";
    else
        std::cout << "No";
       
    return 0;
}