54 lines
1.3 KiB
Haskell
54 lines
1.3 KiB
Haskell
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module Day1 where
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import Data.List
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import ParseLib
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import Util
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main :: IO ()
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main = do
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example <- getFileContents "app/Day1-example.txt"
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input <- getFileContents "app/Day1-input.txt"
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putStrLn "Part 1"
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putStrLn $ "Example: " ++ show (part1 example)
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putStrLn $ "Input: " ++ show (part1 input)
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putStrLn ""
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putStrLn "Part 2"
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putStrLn $ "Example: " ++ show (part2 example)
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putStrLn $ "Input: " ++ show (part2 input)
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part1 :: String -> Int
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part1 input = sum
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$ fmap (unwrap . foldMap Difference)
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$ getPairwise
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$ traverse (Pairwise . sort)
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$ sequenceA
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$ tryparse lexer input
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part2 :: String -> Int
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part2 input = sum $ fmap (\x -> x * count list2 x) list1
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where Line list1 list2 = sequenceA (tryparse lexer input)
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data Line a = Line a a deriving (Show)
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-- Parser code
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lexer :: Parser Char [Line Int]
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lexer = greedy parseLine
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parseLine :: Parser Char (Line Int)
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parseLine = Line <$$> natural <$* token " " <$*> natural <$* token "\n"
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instance Functor Line where
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fmap f (Line x y) = Line (f x) (f y)
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instance Applicative Line where
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pure x = Line x x
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(<*>) (Line fx fy) (Line x y) = Line (fx x) (fy y)
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instance Foldable Line where
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foldMap f (Line x y) = f x `mappend` f y
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instance Traversable Line where
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traverse f (Line x y) = liftA2 Line (f x) (f y)
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