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) {
       
        Scanner sc = new Scanner(System.in);
        int hoge = sc.nextInt();
        char array[] = new char[hoge];
        String a = sc.next();
        int flag = 0;
        for(int i = 0; i < hoge; i++){
            array[i] = a.charAt(i);
        }
        if (hoge % 2 != 0){
            flag = 1;
        }else{
            for(int i = 0; i < hoge/2; i++){
                if(array[i] != array[hoge/2+i]){
                    flag = 1;
                }
            }
        }
        if(flag == 1){
            System.out.println("No");
        }else{
            System.out.println("Yes");
        }    
    }     
}