28 lines
793 B
Haskell
28 lines
793 B
Haskell
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import Aoc
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import Data.List ( nub )
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import Data.Tuple ( swap )
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import Control.Applicative ( (<|>) )
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import Data.Maybe ( fromMaybe )
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parseFile :: [String] -> [((String, String), Int)]
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parseFile = map (\line ->
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let [a, "to", b, "=", dist] = words line in
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((a, b), read dist))
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symLookup :: Eq a => (a, a) -> [((a,a), b)] -> Maybe b
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symLookup a ls = lookup a ls <|> lookup (swap a) ls
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process :: [((String, String), Int)] -> [Int]
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process connections = map (totalLength . adjacents) (permutations cities)
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where
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cities = nub $ concatMap (unpair . fst) connections
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totalLength = sum . map (fromMaybe undefined . (`symLookup` connections))
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part1 :: [Int] -> Int
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part1 = minimum
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part2 :: [Int] -> Int
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part2 = maximum
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main = aocMain (process . parseFile) part1 part2
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