101 lines
3.0 KiB
Haskell
101 lines
3.0 KiB
Haskell
module Main (main) where
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import Control.Monad.State
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import Data.Bifunctor
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import Data.ByteString.Lazy qualified as BL
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import Data.Functor
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import Data.Text (Text)
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import Data.Text qualified as T
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import Data.Text.Encoding (encodeUtf8)
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import Data.Void
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import Test.Tasty
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import Test.Tasty.Golden (goldenVsString)
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import Text.Megaparsec hiding (Pos)
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import Text.Megaparsec.Char
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import Text.Megaparsec.Char.Lexer qualified as Lex
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main :: IO ()
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main =
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defaultMain $
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testGroup
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"tests"
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[ puzzleTest puzzle1
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]
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puzzleTest :: Puzzle a -> TestTree
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puzzleTest p =
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testGroup pt $
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["examples", "real"] <&> \t ->
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withResource (parseFile $ "inputs/" <> t <> "/" <> pt) mempty \input ->
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testGroup t $
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[("1", p.part1), ("2", p.part2)] <&> \(n, pp) ->
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goldenVsString n ("outputs/" <> t <> "/" <> pt <> "/" <> n) $
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BL.fromStrict . encodeUtf8 . pp.solve <$> input
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where
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pt = show p.number
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parseFile fp = maybe (fail "parse failure") pure . parseMaybe (p.parser <* eof) =<< readFile fp
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data Puzzle input = Puzzle
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{ number :: Word
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, parser :: Parsec Void String input
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, part1 :: Part input
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, part2 :: Part input
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}
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data Part input = Part
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{ solve :: input -> Text
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, expected :: Text
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}
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puzzle1 :: Puzzle [(Direction, Inc)]
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puzzle1 =
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Puzzle
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{ number = 1
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, parser = flip sepEndBy newline $ (,) <$> ((char 'L' $> L) <|> (char 'R' $> R)) <*> (Inc <$> Lex.decimal)
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, part1 =
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Part
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{ solve =
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T.show
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. sum
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. flip evalState 50
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. traverse \(d, i) -> state \p ->
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let (_, p') = step i d p
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in (Count if p' == 0 then 1 else 0, p')
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, expected = "3"
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}
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, part2 =
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Part
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{ solve =
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T.show
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. sum
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. flip evalState 50
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. traverse \(d, i) -> state \p ->
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let (c, p') = step i d p
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c' = case d of
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R -> abs c
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L ->
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if
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| p == 0 -> abs c - 1
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| p' == 0 -> abs c + 1
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| otherwise -> abs c
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in (c', p')
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, expected = "6"
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}
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}
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data Direction = L | R
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deriving (Eq, Ord, Show)
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newtype Pos = Pos Int
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deriving newtype (Eq, Ord, Show, Num)
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newtype Inc = Inc Int
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deriving newtype (Eq, Ord, Show, Num)
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newtype Count = Count Int
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deriving newtype (Eq, Ord, Show, Num)
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step :: Inc -> Direction -> Pos -> (Count, Pos)
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step (Inc i) d (Pos p) = bimap Count Pos case d of
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L -> (p - i) `divMod` 100
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R -> (p + i) `divMod` 100
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