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;

/**
 * <p>ClassName:  </p>
 * <p>Description: </p>
 * <p>Company: </p>
 *
 * @author zhangyong
 * @version 1.0.0
 * @date 2019/10/22 7:40
 */
public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String str = in.next();
        if (n % 2 != 0) {
            System.out.println("No");
            return;
        }
        for (int i = 0; i < n / 2; ++i) {
            if (str.charAt(i) != str.charAt(i + n / 2)) {
                System.out.println("No");
                return;
            }
        }
        System.out.println("Yes");
    }
}