AoC/2022/day08/day08.hs

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2022-12-08 07:31:49 +01:00
import Data.List
main :: IO ()
main = do
input <- map (map (subtract 48.fromEnum)) <$> lines <$> readFile "input"
print $ sum $ day8 (fromEnum . any (/=0)) walkLine1 input
print $ maximum $ day8 product walkLine2 input
walkLine2 :: Int -> [Int] -> Int
walkLine2 x (y:ys) = 1 + if y < x then walkLine2 x ys else 0
walkLine2 _ [] = 0
walkLine1 :: Int -> [Int] -> Int
walkLine1 x (y:ys) = if y < x then walkLine1 x ys else 0
walkLine1 _ [] = 1
checkPoint :: (Int -> [Int] -> Int) -> (Int,Int) -> [[Int]] -> [Int]
checkPoint f (x,y) field = [f num line | line <- [lineX1,lineX2,lineY1,lineY2]]
where num = field !! y !! x
lineX1 = drop (x+1) $ field !! y
lineX2 = reverse $ take x $ field !! y
lineY1 = drop (y+1) $ (transpose field) !! x
lineY2 = reverse $ take y $ (transpose field) !! x
day8 :: ([Int] -> Int) -> (Int -> [Int] -> Int) -> [[Int]] -> [Int]
day8 f1 f2 field = [f1 $ checkPoint f2 (x,y) field | x<-[0..(subtract 1 $ length $ head field)], y<-[0..(subtract 1 $ length field)]]