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.*;
import java.util.Map.Entry;
 
 
 class Main {
	 static int mod =  (int) (Math.pow(10,9)+7);
	 static List<ArrayList<Integer>>  list = new ArrayList<ArrayList<Integer>>();
    public static void main(String[] args) {
    
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        String S = sc.next();
        
        String T1 = S.substring(0,N/2);
        String T2 = S.substring(N/2);

        if(T1.equals(T2)) {
            System.out.println("Yes");        	
        } else {
            System.out.println("No");        	        	
        }
                		
    }
}