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: Accepted)

#include<iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <cmath>
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
int main(){
  	int N;
  	string S;
  	cin >> N >> S;
  	
  	if(N%2==1){
  		cout << "No" <<endl;
  		return 0;
  	}
  	for(int i=0;i<N/2;i++){
  		if(S[i]!=S[i+N/2]){
  			cout << "No" <<endl;
  			return 0;
  		}
  	}
  	
  	cout << "Yes" <<endl;

  	return 0;
}