Palindrome Rearranging

Haskell Palindrome Rearranging

import qualified Data.Map.Strict as Map

palindromeRearranging :: String -> Bool
palindromeRearranging inputString = length (filter odd (Map.elems counts)) <= 1
  where
    counts = Map.fromListWith (+) [(c, 1 :: Int) | c <- inputString]

This counts character frequency and checks whether the string has the right number of odd counts to form a palindrome.