AoC2019/day10.hs

import Data.List as List
import Debug.Trace as Trace

main = do
    content <- getContents
    let layers =  lines content
    let indexlayers = map(\x-> mapInd(\x y -> (y,x)) x ) layers
    let points = concat (mapInd(\x y->map(\x->((fst x,y),snd x))x) $ indexlayers)
    let asteroids = (map fst (filter(\(x,y) -> y == '#' ) points))
    let maximum = List.maximum(map(\x-> length(getViews (changeCoordinate (asteroids) x))) (asteroids))
    let station = head $ map(\x-> fst x) $ filter(\x-> snd x == maximum )(map(\x-> (x,( length(getViews (changeCoordinate asteroids x))))) (asteroids))
    let changedAsteroids = changeCoordinate asteroids station 
    let sortedAsteroids = sortBy sortDistance changedAsteroids
    let views = getViews sortedAsteroids
    let sortedViews = sortBy sortDegree views
    let destroyed = getDestroyOrder sortedAsteroids []
    let destroyNormal = map (\(a,b)-> (((fst station) + a),((snd station) + b))) destroyed
    putStrLn(show maximum)
    putStrLn(show station)
    putStrLn(show  views)
    putStrLn(show sortedViews)
    putStrLn(show $ map degree destroyed)
    putStrLn(show $ destroyNormal!!19)
mapInd :: (a -> Int -> b) -> [a] -> [b]
mapInd f l = zipWith f l [0..]

getDestroyOrder :: [(Int,Int)] -> [(Int,Int)] -> [(Int,Int)]
getDestroyOrder ast out
   | length ast > 0 = do
             let views = getViews ast
             let sortedViews = sortBy sortDegree views
             let newout = out ++ sortedViews
             let newast = ast \\ sortedViews
             getDestroyOrder newast newout
   | otherwise = out

sortDistance ((a,b)) ((a2,b2))
  | abs(a) + abs(b) > abs(a2) + abs(b2) = GT
  | abs(a) + abs(b) < abs(a2) + abs(b2) = LT
  | abs(a) + abs(b) == abs(a2) + abs(b2) = EQ

sortDegree a b
  | degree a > degree b = GT
  | degree a < degree b = LT
  | degree a == degree b = EQ

getViews :: [(Int,Int)] -> [(Int,Int)]
getViews xs = foldl getView [] xs

changeCoordinate :: [(Int, Int)] -> (Int,Int) -> [(Int,Int)]
changeCoordinate xs (a,b) = (delete (0,0)( (map(\(x,y) -> ((x-a),(y-b)))xs))) 

getView :: [(Int,Int)] -> (Int,Int) -> [(Int,Int)]
getView xs y 
       |notElem (reduce y) (map reduce xs) = xs ++ [y]
       |otherwise = xs

reduce :: (Int,Int) -> (Int,Int) 
reduce (a,b) = ((div a (gcd a b)),(div b (gcd a b)))

degree :: (Int,Int) -> Double
degree (a,b) = do
       let x = fromIntegral a
       let y = fromIntegral b
       y / x