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: Wrong Answer)

import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    int N = sc.nextInt();
    String S = sc.next();

    String rp = S.substring(0, 1+S.substring(1).indexOf(S.charAt(0)));

    if (rp.equals("")) {
      System.out.println("No");
      return; 
    }

    for (int i = 0; i < N; i += rp.length()) {
      try {
        if (!rp.equals(S.substring(i, i + rp.length()))) {
          System.out.println("No");
          return;   
        }
      } catch (Exception e) {
        System.out.println("No");
        return; 
      }
    }
    
    System.out.println("Yes");
  }
}