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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
	    // 入力受付
	    Scanner scan = new Scanner(System.in);
	    int n = scan.nextInt();
	    String str = scan.next();

	    if(n % 2 != 0){
	        System.out.println("No");
	        return;
	    }

	    int a = n / 2;
	    String splitStrA = str.substring(0, a);
	    String splitStrB = str.substring(a);

	    if(splitStrA.equals(splitStrB)){
	        System.out.println("Yes");
	    }else{
	        System.out.println("No");
	    }

	}
}