22 lines
636 B
Haskell
22 lines
636 B
Haskell
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import Data.List -- sort
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mapTuple :: (a -> b) -> (a, a) -> (b, b)
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mapTuple f (a1, a2) = (f a1, f a2)
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-- helper function for split
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splitH :: [a] -> [a] -> [a] -> ([a], [a])
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splitH ls rs (x:xs) = splitH rs (ls++[x]) xs
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splitH ls rs _ = (ls, rs)
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-- split: split list into two by alternating between left and right
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split :: [a] -> ([a], [a])
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split = splitH [] []
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-- calculates the sum of the absolute distance between two lists
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dist :: Int -> ([Int], [Int]) -> Int
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dist acc (l:ls, r:rs) = dist (acc + abs (r - l)) (ls, rs)
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dist acc _ = acc
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main = interact $ show . dist 0 . mapTuple sort . split . map (read :: String -> Int) . words
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