45 lines
1.1 KiB
Haskell
45 lines
1.1 KiB
Haskell
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{-# LANGUAGE ImportQualifiedPost #-}
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE TypeApplications #-}
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module Day05 (parse, solveA) where
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import Control.Monad (foldM)
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import Control.Monad qualified as T
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import Data.Either (fromLeft)
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import Data.Maybe (fromMaybe, isNothing)
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import Data.Text (Text)
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import Data.Text qualified as T
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parse :: Text -> [Text]
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parse = T.lines
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isVovel :: Char -> Bool
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isVovel c = elem @[] c "aeiou"
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isWrong :: String -> Bool
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isWrong cs = cs `elem` ["ab", "cd", "pq", "xy"]
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isNice :: Text -> Bool
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isNice = maybe False (check . snd) . foldM next ('_', (False, 0)) . T.unpack
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where
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check :: (Bool, Int) -> Bool
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check (double, vowels) = double && vowels >= 3
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next :: ((Char, (Bool, Int)) -> Char -> Maybe (Char, (Bool, Int)))
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next (prev, (double, vowels)) char =
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let double' = double || prev == char
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vowels' = if isVovel char then vowels + 1 else vowels
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in if isWrong [prev, char]
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then Nothing
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else Just (char, (double', vowels'))
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solveA :: [Text] -> Int
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solveA = length . filter isNice
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test :: Text
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test = "dvszwmarrgswjxmbau"
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-- $> isNice test
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solveB = undefined
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