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<bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int i=0 ; i<(n) ; i++)
#define repr(i,n) for(int i=(n) ; i>=0 ; i--)
#define ALL(x) (x).begin(),(x).end()

typedef long long ll;
typedef unsigned long long ull;
 
const ll INF = 1LL<<60;
const int MINF = 1e9;
const int MOD = 1e9+7;

using vi = vector<int>;
using vii = vector<vi>;

template<typename T> bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<typename T> bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

template<typename T>
T GCD(T a,T b){ return b ? GCD(b,a%b) : a ;}
template<typename T>
T LCM(T a,T b){ return a*b / GCD(a,b) ;}

int main(){
    string s;cin >> s;
    int n = s.size();
    string s1 = s.substr(0,(n-1)/2);
    string s2 = s.substr((n+3)/2-1);

    int s1_size = s1.size();
    for(int i=0;i<s1_size/2;i++){
        if(s1[i] != s1[s1_size-1]){
            cout << "No" << endl;
            return 0;
        }
    }
    int s2_size = s2.size();
    for(int i=0;i<s2_size/2;i++){
        if(s2[i] != s2[s2_size-1]){
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
    return 0;
}