35 lines
886 B
Haskell
35 lines
886 B
Haskell
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module Day10_1 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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import Data.List (sort)
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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 ')' = 1
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score ']' = 2
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score '}' = 3
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score '>' = 4
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matchBraces :: [Char] -> [Char] -> Maybe [Char]
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matchBraces [] [] = Nothing
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matchBraces acc [] = Just acc
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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 = Nothing
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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 . (\x -> x !! (length x `div` 2)) . sort $ map (foldl (\acc x -> score x + (acc * 5)) 0) $ mapMaybe (matchBraces []) routes
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hClose input
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