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part 2

This commit is contained in:
Gattix 2023-12-12 18:09:34 +01:00
parent 621fcf2b23
commit 8879ae24f9
1 changed files with 9 additions and 8 deletions
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17
2023/day11/day11.hs
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@ -1,3 +1,4 @@
import Control.Arrow
import Data.Function
import Data.Ix
import Control.Lens
@ -6,10 +7,10 @@ import Data.Ord
import Linear.V2
main :: IO ()
main = interact $ show . day11 . parse . lines
main = interact $ show . (day11 1 &&& day11 999999) . parse . lines
day11 :: [V2 Int] -> Int
day11 = (`div` 2) . sum . f . (expand =<< findEmptyRows)
day11 :: V2 Int -> [V2 Int] -> Int
day11 n = (`div` 2) . sum . f . (expandBy n =<< findEmptyRows)
where f xs = [sum $ abs $ x-y | x<- xs, y<- xs]
parse :: [String] -> [V2 Int]
@ -17,9 +18,9 @@ parse = map fst . filter ((=='#') . snd) . concat . zipWith (map . f) [0..] . ma
where f x (y,z) = (V2 y x, z)
expand :: [V2 Int] -> [V2 Int] -> [V2 Int]
expand [] input = input
expand (d:ds) input = expand (map (moveCoord d) ds) (map (moveCoord d) input)
expandBy :: V2 Int -> [V2 Int] -> [V2 Int] -> [V2 Int]
expandBy _ [] input = input
expandBy n (d:ds) input = expandBy n (map (moveCoord n d) ds) (map (moveCoord n d) input)
findEmptyRows :: [V2 Int] -> [V2 Int]
@ -29,6 +30,6 @@ findEmptyRows input = map flipV2 (findEmptyRows $ map flipV2 input) ++ findEmpt
maxP = maximumBy (comparing (view _x)) input
flipV2 (V2 x y) = V2 y x
moveCoord :: V2 Int -> V2 Int -> V2 Int
moveCoord x y = if y^.p >= x ^.p then y + signum x else y
moveCoord :: V2 Int -> V2 Int -> V2 Int -> V2 Int
moveCoord n x y = if y^.p >= x ^.p then y + n * signum x else y
where p = if x^._x == 0 then _y else _x