some haskell exercises

mindiff.hs

#! /usr/bin/runhaskell

import Control.Monad
import Data.List

mapSucc :: (a -> a -> b) -> [a] -> [b]
mapSucc _ []  = []
mapSucc f [x] = error "can't call mapSucc with a list of only one element"
mapSucc f [x, y] = [f x y]
mapSucc f (x:y:xs) = f x y : mapSucc f (y:xs)

main = do
  n <- getLine
  xs <- replicateM (read n) getLine
  putStrLn . show . minimum . mapSucc (flip (-)) . sort . map read $ xs