AoC2019/day12.hs

import Data.List.Split
import Data.List
import Data.Char as Char
import Linear.V3

main = do
      moons <- map createMoon <$> map getList <$> map cleanString <$> lines <$> getContents
      --let newMoons = calculateMoons moons 1000
      --let ernergy = sum $ map getErnergy newMoons
      let xAxis = getXAxis moons
      let loopx = findLoop xAxis xAxis 0
      let yAxis = getYAxis moons 
      let loopy = findLoop yAxis yAxis 0
      let zAxis = getZAxis moons 
      let loopz = findLoop zAxis zAxis 0
      let result = foldl1 lcm [loopx, loopy, loopz] 
      --mapM putStrLn ( map show newMoons )
      --putStrLn ( show ernergy)
      putStrLn(show result)

data Moon = Moon{ position :: V3 Int
                  ,velocity :: V3 Int
                } deriving Show

getList :: String -> [Int]
getList = map read . splitOn ", "

cleanString :: String -> String
cleanString xs = xs \\ "<>xyz==="

createMoon :: [Int] -> Moon
createMoon [x,y,z] = Moon (V3 x y z) (V3 0 0 0)

stepGravity :: [Moon] -> [Moon]
stepGravity xs = map (\(p,v) -> Moon p v) $ zip (newPos) newVel
            where newVel = zipWith (+) (getVel xs) (gravity $ getPos xs)
                  newPos = zipWith (+) (getPos xs) (newVel)  

gravity :: (Num a, Eq a)=> [a] -> [a]
gravity xs = [sum [signum $ x-y | x<-xs, y/=x] | y<-xs]

calculateMoons :: [Moon] -> Int -> [Moon]
calculateMoons xs 0 = xs
calculateMoons xs n = calculateMoons (stepGravity xs) (n-1)

findLoop :: ([Int],[Int]) -> ([Int],[Int]) -> Int -> Int
findLoop pos start c  
     | pos /= start || c == 0 = findLoop (stepAxis pos) start (c+1)
     | pos == start = c

stepAxis :: ([Int],[Int]) -> ([Int],[Int])
stepAxis (pos,vel) = (newPos, newVel)
         where newVel = zipWith (+) (vel) (gravity pos)
               newPos = zipWith (+) (pos) (newVel)

getPos :: [Moon] -> [V3 Int]
getPos xs = map(\x -> position x) xs

getVel :: [Moon] -> [V3 Int]
getVel xs = map(\x -> velocity x) xs

getErnergy :: Moon -> Int
getErnergy (Moon pos vel)  = (sum $ abs pos) * (sum $ abs vel)

getXAxis :: [Moon] -> ([Int],[Int])
getXAxis xs = (pos,vel)
           where   pos = map(\x -> getX $ position x) xs
                   vel = map(\x -> getX $ velocity x) xs

getZAxis :: [Moon] -> ([Int],[Int])
getZAxis xs = (pos,vel)
           where   pos = map(\x -> getZ $ position x) xs
                   vel = map(\x -> getZ $ velocity x) xs

getYAxis :: [Moon] -> ([Int],[Int])
getYAxis xs = (pos,vel)
           where   pos = map(\x -> getY $ position x) xs
                   vel = map(\x -> getY $ velocity x) xs

getX :: V3 Int -> Int
getX (V3 x y z) = x

getY :: V3 Int -> Int
getY (V3 x y z) = y

getZ :: V3 Int -> Int
getZ (V3 x y z) = z