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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

module Main where

import Data.Char
import Data.List

main :: IO ()
main = do
  num <- fmap read getLine
  str <- getLine
  if (mod num 2) == 1
    then putStrLn "No"
    else putStrLn $ discrimination num str

discrimination:: Int -> String -> String
discrimination n str = 
  let half = n `div` 2
      firstHalf = take half str
      secondHalf = reverse $ take half $ reverse str
  in if firstHalf == secondHalf
    then "Yes"
    else "No"