Problem:
Score : 200 points

Problem Statement

A string S of an odd length is said to be a strong palindrome if and only if all of the following conditions are satisfied:

S is a palindrome.

Let N be the length of S. The string formed by the 1-st through ((N-1)/2)-th characters of S is a palindrome.

The string consisting of the (N+3)/2-st through N-th characters of S is a palindrome.

Determine whether S is a strong palindrome.

Constraints

S consists of lowercase English letters.

The length of S is an odd number between 3 and 99 (inclusive).

Input

Input is given from Standard Input in the following format:

S

Output

If S is a strong palindrome, print Yes;
otherwise, print No.

Sample Input 1

akasaka

Sample Output 1

Yes

S is akasaka.

The string formed by the 1-st through the 3-rd characters is aka.

The string formed by the 5-th through the 7-th characters is aka.
All of these are palindromes, so S is a strong palindrome.

Sample Input 2

level

Sample Output 2

No

Sample Input 3

atcoder

Sample Output 3

No

Solution in Haskell (GHC 7.10.3) (judge verdict: Accepted)

import           Control.Monad
import           Control.Monad.ST
import qualified Data.Array                    as A
import qualified Data.Array.ST                 as ST
import qualified Data.Array.Unboxed            as AU
import qualified Data.ByteString.Char8         as BS
import           Data.Char
import qualified Data.Foldable                 as DF
import           Data.Int
import qualified Data.IntMap                   as IM
import           Data.List
import qualified Data.Map                      as M
import           Data.Maybe
import           Data.Ord
import qualified Data.Set                      as S
import qualified Data.Sequence                 as SQ
import           Data.Time
import qualified Data.Vector                   as V
import qualified Data.Vector.Mutable           as VM
import qualified Data.Vector.Unboxed           as VU
import qualified Data.Vector.Unboxed.Mutable   as VUM

readInt = map (fst . fromJust . BS.readInt) . BS.words <$> BS.getLine
readInts n = replicateM n readInt
readString = map BS.unpack . BS.words <$> BS.getLine
readStrings n = replicateM n <$> readString
toPair [x, y] = (x, y)

main = do
  [s] <- readString
  putStrLn $ solve s

f s | s == reverse s = True
    | otherwise      = False

solve s
  | f s && f (take ((length s - 1) `div` 2) s) && f
    (take ((length s - 1) `div` 2) $ reverse s)
  = "Yes"
  | otherwise
  = "No"