29 lines
875 B
Haskell
29 lines
875 B
Haskell
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{-# LANGUAGE LambdaCase #-}
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import Data.List.Split
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import Linear.V3
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main = do
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moons <- parseContent <$> readFile "testinput"
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let velocity = replicate 4 $ V3 0 0 0
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print $ energy $ step (moons,velocity) 1000
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removeJunk :: String -> String
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removeJunk xs = [ x | x <- xs, x `notElem` " <>xyz=" ]
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parseContent :: String -> [V3 Int]
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parseContent = map ((\[x,y,z]->V3 x y z) . map read . splitOn ",") . lines . removeJunk
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gravity :: [V3 Int] -> [V3 Int]
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gravity xs = [sum [signum $ x-y | x<-xs, y/=x] | y<-xs]
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step :: ([V3 Int],[V3 Int]) -> Int -> ([V3 Int],[V3 Int])
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step (moons,vel) 0 = (moons,vel)
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step (moons,vel) n = step (zipWith (+) moons newVel,newVel) (n-1)
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where dVel = gravity moons
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newVel = zipWith (+) vel dVel
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energy :: ([V3 Int],[V3 Int]) -> Int
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energy (x,y) = sum $ zipWith (*) (geten x) (geten y) where
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geten = map (sum . abs)
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