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 Scala (2.11.7) (judge verdict: Accepted)

import java.util.Scanner
import java.io.PrintWriter

object Main {
  def main(args: Array[String]): Unit = {
    val sc = new Scanner(System.in)
    val pw = new PrintWriter(System.out)

    val n = sc.nextInt()
    val s = sc.next()
    if (n % 2 == 1) {
      pw.println("No")
    } else {
      if (s.substring(0, n / 2) == s.substring(n / 2)) {
        pw.println("Yes")
      } else {
        pw.println("No")
      }
    }

    pw.flush()
  }
}