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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
namespace B___Echo
{
    static class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            string s = Console.ReadLine();
            if (s.Length % 2 == 0)
            {
                string[] array = s.MySplit(s.Length / 2);
                if (array[0] == array[1])
                {
                    Console.WriteLine("Yes");
                }
                else
                {
                    Console.WriteLine("No");
                }
            }
            else
            {
                Console.WriteLine("No");
            }

        }
        static string[] MySplit(this string str, int count)
        {
            var list = new List<string>();
            int length = (int)Math.Ceiling((double)str.Length / count);

            for (int i = 0; i < length; i++)
            {
                int start = count * i;
                if (str.Length <= start)
                {
                    break;
                }
                if (str.Length < start + count)
                {
                    list.Add(str.Substring(start));
                }
                else
                {
                    list.Add(str.Substring(start, count));
                }
            }

            return list.ToArray();
        }
    }
}