33 lines
764 B
Haskell
33 lines
764 B
Haskell
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module Day10 where
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import System.IO (openFile, IOMode (ReadMode), hClose, hGetContents)
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import Data.Maybe (mapMaybe)
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closing :: Char -> Char
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closing '(' = ')'
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closing '[' = ']'
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closing '{' = '}'
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closing '<' = '>'
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score :: Char -> Int
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score ')' = 3
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score ']' = 57
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score '}' = 1197
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score '>' = 25137
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matchBraces :: [Char] -> [Char] -> Maybe Char
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matchBraces _ [] = Nothing
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matchBraces acc (x:xs)
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| x `elem` ['(', '[', '{', '<'] = matchBraces (closing x : acc) xs
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| x == head acc = matchBraces (tail acc) xs
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| otherwise = Just x
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main :: IO ()
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main = do
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input <- openFile "inputs/10.txt" ReadMode
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contents <- hGetContents input
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let routes = lines contents
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print . sum . map score $ mapMaybe (matchBraces []) routes
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hClose input
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