62 lines
1.6 KiB
Haskell
62 lines
1.6 KiB
Haskell
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module Day3.Main (main) where
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import System.IO
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import Data.Char
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import Data.List.Split
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main :: IO ()
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main = do
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putStrLn "Day 3"
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handle <- openFile "app/Day3/input" ReadMode
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contents <- hGetContents handle
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let r1 = part1 contents
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putStrLn $ "part 1: " ++ show r1
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let r2 = part2 contents
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putStrLn $ "part 2: " ++ show r2
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type Rucksack = (String, String)
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parseData :: String -> [Rucksack]
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parseData input = compartments
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where
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rucksacks = lines input
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compartmentSize = map ((`div` 2) . length) rucksacks
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firstCompartments = map (\(s, r) -> take s r) (zip compartmentSize rucksacks)
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secondCompartments = map (\(s, r) -> drop s r) (zip compartmentSize rucksacks)
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compartments = zip firstCompartments secondCompartments
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inBoth :: Eq a => [a] -> [a] -> [a]
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inBoth a b = [x | x <- a, y <- b, x == y]
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allEqual :: Eq a => [a] -> Bool
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allEqual [] = True
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allEqual (x:xs) = all (== x) xs
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inAll :: Eq a => [[a]] -> [a]
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inAll xs = map ((!! 0) . snd) res
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where
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prod = sequence xs
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equal = map allEqual prod
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res = filter fst (zip equal prod)
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getValue :: Char -> Int
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getValue a | a >= 'a' && a <= 'z' = ord a - ord 'a' + 1
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getValue a | a >= 'A' && a <= 'Z' = ord a - ord 'A' + 1 + 26
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part1 :: String -> Int
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part1 contents = sum values
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where
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both = map (uncurry inBoth) (parseData contents)
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single = map (!! 0) both
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values = map getValue single
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part2 :: String -> Int
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part2 contents = sum values
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where
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groups = chunksOf 3 (lines contents)
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badges = map ((!! 0) . inAll) groups
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values = map getValue badges
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