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 = Integer.parseInt(sc.nextLine());
    String s = sc.nextLine();
    sc.close();
    if (n % 2 == 1) {
      System.out.println("No");
      return;
    }
    for (int i = 0; i < n / 2; i++) {
      char c1 = s.charAt(i);
      char c2 = s.charAt(i + n / 2);
      if (c1 != c2) {
        System.out.println("No");
        return;
      }
    }
    System.out.println("Yes");
  }
}