45 lines
1.3 KiB
Haskell
45 lines
1.3 KiB
Haskell
{-# LANGUAGE OverloadedStrings #-}
|
|
{-# LANGUAGE ViewPatterns #-}
|
|
|
|
import Data.List (foldl')
|
|
import Data.Map (Map)
|
|
import qualified Data.Map as M
|
|
import Data.Text (Text)
|
|
import qualified Data.Text as T
|
|
import Lib (readFile')
|
|
|
|
main :: IO ()
|
|
main = do
|
|
input <- break (== T.empty) . T.lines <$> readFile' "day5.in"
|
|
let (crates, cmds) = parse input
|
|
putStr "Q1: "
|
|
print $ moveCrates T.reverse crates cmds
|
|
putStr "Q2: "
|
|
print $ moveCrates id crates cmds
|
|
|
|
moveCrates :: (Text -> Text) -> [Text] -> [(Int, Int, Int)] -> Text
|
|
moveCrates f crates' cmds = head . T.transpose . M.elems $ foldl' move crates cmds
|
|
where
|
|
crates :: Map Int Text
|
|
crates = M.fromList $ zip [0 ..] crates'
|
|
move :: Map Int Text -> (Int, Int, Int) -> Map Int Text
|
|
move c (n, x, y) =
|
|
let (h, t) = T.splitAt n $ c M.! x
|
|
in M.update (Just . (<>) (f h)) y $ M.insert x t c
|
|
|
|
-- ugly code vs line length <= 90 🤔
|
|
parse :: ([Text], [Text]) -> ([Text], [(Int, Int, Int)])
|
|
parse (crates, cmds) =
|
|
( [ T.filter (/= ' ') x
|
|
| (i, x) <- zip [0 ..] (T.transpose $ init crates),
|
|
i `mod` 4 == 1
|
|
],
|
|
map
|
|
( ( \["move", T.unpack -> n, "from", T.unpack -> x, "to", T.unpack -> y] ->
|
|
(read n, read x - 1, read y - 1)
|
|
)
|
|
. T.words
|
|
)
|
|
$ tail cmds
|
|
)
|