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.*;
public class Main
{
  public static void main(String args[])
  {
    Scanner sc=new Scanner(System.in);
    int n=sc.nextInt();
    sc.nextLine();
    String s=sc.nextLine();
    if(n%2!=0)
      System.out.println("No");
    else
    {
      boolean b=true;
      for(int i=n/2-1,j=n-1;i>=0;i--,j--)
      {
        if(s.charAt(i)!=s.charAt(j))
        {
          b=false;
          break;
        }
      }
      if(b)
        System.out.println("Yes");
      else
        System.out.println("No");
    }
  }
}