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 n=sc.nextInt();
		if(n%2==1) {
			System.out.println("No");
		}else {
			String s=sc.next();
		    int a=n/2;
		    int c=0;
		    for(int i=0;a<n;i++) {
		    	if(s.charAt(i)==s.charAt(a)) {
		    		c++;
		    	}a++;

		    }
		    if(c==n/2) {
		    	System.out.println("Yes");
		    }else {
		    	System.out.println("No");
		    }
		}

	}

}