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;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
// Mainに書き換え！

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        // 整数の入力
        int len = Integer.parseInt(sc.next());
        String str = sc.next();

        Pattern dupPattern = Pattern.compile("([ \\w]+)\\1", Pattern.CASE_INSENSITIVE);
        Matcher matcher = dupPattern.matcher(str);

        while (matcher.find()) {
            str = str.replaceAll("([ \\w]+)\\1", "$1");
        }
        //System.out.println(str);

        if ((len != str.length())&&(len % str.length()) == 0) {
            System.out.println("Yes");

        }else{
            System.out.println("No");

        }

    }
}