43 lines
1.1 KiB
Haskell
43 lines
1.1 KiB
Haskell
module Puzzles.Day5 (puzzle) where
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import Control.Monad
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import Data.Functor
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import Data.List.Extra
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import Data.Maybe
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import Data.Text.Lazy qualified as TL
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import Puzzle
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import Text.Megaparsec hiding (some)
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import Text.Megaparsec.Char
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import Text.Megaparsec.Char.Lexer qualified as Lex
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puzzle :: Puzzle
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puzzle =
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Puzzle
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{ number = 5
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, parser = do
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ranges <- flip sepEndBy newline $ Range <$> Lex.decimal <* single '-' <*> Lex.decimal
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void newline
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vals <- sepEndBy Lex.decimal newline
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pure (ranges, vals)
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, parts =
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[ \(ranges, vals) ->
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TL.show
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. length
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. map fst
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. filter (notNull . snd)
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$ map
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(\v -> (v, mapMaybe (\r -> guard (isInRange v r) $> r) ranges))
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vals
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]
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, extraTests = mempty
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}
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data Range = Range
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{ lower :: Int
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, upper :: Int
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}
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deriving (Eq, Ord, Show)
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isInRange :: Int -> Range -> Bool
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isInRange n r = n >= r.lower && n <= r.upper
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