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<iostream>
#include<cstring>
#include<algorithm>
#include<cmath>
#define mm(a,x) memset(a,x,sizeof(a))
#define sync std::ios::sync_with_stdio(false);std::cin.tie(0)
#define ll long long
using namespace std;
int main(void)
{
    sync;
    string s;
    cin>>s;
    s="#"+s;
    int n=s.size();
    string s1=s.substr(1,(n-1)/2);
    string s2=s.substr((n+3)/2);
    bool flag=true;
    if(!equal(s.begin()+1,s.end(),s.rbegin()))
        flag=false;
    if(!equal(s1.begin(),s1.end(),s1.rbegin()))
        flag=false;
    if(!equal(s2.begin(),s2.end(),s2.rbegin()))
        flag=false;
    if(flag)
        cout<<"Yes"<<endl;
    else
        cout<<"No"<<endl;
    return 0;
}