48 lines
1.4 KiB
Haskell
48 lines
1.4 KiB
Haskell
import Data.List (transpose, delete)
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import Data.List.Split (chunksOf, splitOn)
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import Data.Char (isSpace)
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import Debug.Trace (traceShowId, traceShow)
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data Command = Move {amount :: Int, from :: Int, to :: Int} deriving Show
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type State = [[Char]]
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parseInit :: [String] -> State
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parseInit s = map (dropWhile isSpace . init . (!!1)) (chunksOf 4 $ transpose s)
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parseCmds :: [String] -> [Command]
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parseCmds s = map readCmd s where
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readCmd s = let w = words s in Move (read (w !! 1)) (read (w !! 3) - 1) (read (w !! 5) - 1)
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listApp :: Int -> (a -> a) -> [a] -> [a]
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listApp 0 f (x:xs) = f x : xs
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listApp n f (x:xs) = x : listApp (n-1) f xs
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move1 :: (Int, Int) -> State -> State
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move1 (from, to) state = addTo $ popFrom state where
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popFrom = listApp from tail
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elem = head (state !! from)
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addTo = listApp to (elem:)
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moveN :: Command -> State -> State
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moveN (Move 0 from to) = id
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moveN (Move n from to) = moveN (Move (n-1) from to) . move1 (from,to)
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moveN2 :: Command -> State -> State
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moveN2 (Move amount from to) state = addTo $ popFrom state where
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popFrom = listApp from (drop amount)
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elems = take amount (state !! from)
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addTo = listApp to (elems ++ )
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main :: IO ()
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main = do
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[init', cmds'] <- splitOn [""] . lines <$> getContents
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let init = parseInit init'
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let cmds = parseCmds cmds'
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putStr "part 1: "
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print $ map head $ foldl (flip moveN) init cmds
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putStr "part 2: "
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print $ map head $ foldl (flip moveN2) init cmds
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