26 lines
761 B
Haskell
26 lines
761 B
Haskell
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{-# LANGUAGE TupleSections #-}
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module Day2B where
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import Data.List (find)
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import qualified Data.Sequence as S
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import qualified Data.Foldable as F
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dist' :: Int -> (S.Seq Char) -> String -> String -> (Int, String)
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dist' n common (a:x) (b:y)
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| a == b = dist' n (common S.|> a) x y
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| otherwise = dist' (n + 1) common x y
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dist' n common _ _ = (n, F.toList common)
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dist :: String -> String -> (Int, String)
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dist = dist' 0 S.empty
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combinations :: [String] -> [(String, String)]
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combinations (x:y:xs) = (x, y):(combinations (y:xs))
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combinations [] = []
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distances :: [(String, String)] -> String
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distances xs = result
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where Just(_, result) = find (\(x, _) -> x == 1) $ map (uncurry dist) xs
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main :: IO ()
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main = interact $ distances . combinations . lines
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