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){
		try(Scanner sc = new Scanner(System.in)) {

			int n = sc.nextInt();
			
			String s = sc.next();
			
			if ( n % 2 != 0 ) {
				System.out.println("No");
				return;
			}
			
			boolean isMatch = true;
			for(int i = 0 ; i < n / 2 ; i++ ) {
				if ( s.charAt(i) != s.charAt(n/2 + i) ) {
					isMatch = false;
				}
			}
			
			System.out.println(isMatch ? "Yes" : "No");
			
		}
	}
}