15 lines
321 B
Haskell
15 lines
321 B
Haskell
import Control.Arrow
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main :: IO ()
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main = do
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input <- parse <$> readFile "input"
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print $ (day09 &&& day09 . map reverse) input
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parse :: String -> [[Int]]
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parse = map (map read . words) . lines
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day09 :: [[Int]] -> Int
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day09 =
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sum .
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map (sum . map last . takeWhile (not . null) . iterate (zipWith (-) =<< tail))
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