Problem:
Score : 200 points

Problem Statement

Given are a positive integer N and a string S of length N consisting of lowercase English letters.

Determine whether the string is a concatenation of two copies of some string.
That is, determine whether there is a string T such that S = T + T.

Constraints

1 \leq N \leq 100

S consists of lowercase English letters.

|S| = N

Input

Input is given from Standard Input in the following format:

N
S

Output

If S is a concatenation of two copies of some string, print Yes; otherwise, print No.

Sample Input 1

6
abcabc

Sample Output 1

Yes

Let T = abc, and S = T + T.

Sample Input 2

6
abcadc

Sample Output 2

No

Sample Input 3

1
z

Sample Output 3

No

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<bits/stdc++.h>
#define ll long long
using namespace std;
using u64 = uint64_t;
using u128 = __uint128_t;

int main(){ 
    int N;
    string S;
    cin>>S;
    if(N%2==1){
        cout<<"No"<<endl;
        return 0;
    }else{
        for(int i=0;i<N/2;i++){
            if(S[i]!=S[N/2+i]){
                cout<<"No"<<endl;
                return 0;
            }
        }
    }
    cout<<"Yes"<<endl;
    return 0;
}