Mushroom eater puzzle

mushroom.hs

import System.IO
import Control.Monad

solve_v1 :: [Int] -> Int
solve_v1 (a:[]) = 0
solve_v1 (a:b:c) = (if a > b then a - b else 0) + (solve_v1 (b:c))

min_dist :: [Int] -> Int
min_dist (a:[]) = 0
min_dist (a:b:c) = if a > b then max (min_dist (b:c)) (a - b) else min_dist (b:c)

solve_v2 :: [Int] -> Int -> Int
solve_v2 (a:[]) _ = 0
solve_v2 (a:b:c) d = (min a d) + (solve_v2 (b:c) d)

main = do
  fin <- openFile "mushroom.in" ReadMode
  examples <- hGetLine fin
  forM_ (replicate (read examples :: Int) fin) $ \handle -> do
    _ <- hGetLine handle
    input <- hGetLine handle
    items <- return $ map (\a -> read a :: Int) $ words input
    print $ solve_v1 items
    print $ solve_v2 items (min_dist items)