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40 lines
1.2 KiB
Haskell
40 lines
1.2 KiB
Haskell
module Days.Day03 (day03, splitInto, commonItem) where
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import AOC (Solution (..))
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import qualified Data.Text as T
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import Data.List
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import Data.Maybe
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import Debug.Trace
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day03 :: Solution
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day03 = Solution parseInput part1 part2
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parseInput :: T.Text -> [[String]]
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parseInput input = go [] allLines
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where
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go acc [] = reverse acc
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go acc xs = go (take 3 xs : acc) (drop 3 xs)
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allLines = map T.unpack $ T.lines input
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priority :: Char -> Int
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priority = (+1) . fromJust . flip elemIndex (['a'..'z'] ++ ['A'..'Z'])
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splitInto :: Int -> [a] -> [[a]]
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splitInto s xs = go [] xs
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where
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go acc [] = reverse acc
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go acc xs' = go (take takeInt xs' : acc) (drop takeInt xs')
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takeInt = round $ (fromIntegral $ length xs) / (fromIntegral s)
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commonItem :: Eq a => [[a]] -> [a]
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commonItem [] = []
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commonItem xs = foldl1' intersect xs
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part1 :: [[String]] -> Int
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part1 input = sum $ map (priority . head . commonItem . splitInto 2) (concat input)
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part2 :: [[String]] -> Int
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part2 input = sum $ map (priority . head . commonItem) input
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-- part2 input = sum $ map (sum . map (priority . head . commonItem . splitInto 2)) (traceShowId input)
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-- part2 input = traceShowId input
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