63 lines
1.7 KiB
Haskell
63 lines
1.7 KiB
Haskell
import Control.Lens
|
|
import Data.List.Split
|
|
import Linear.V2
|
|
|
|
type Sensor = (V2 Int, V2 Int)
|
|
|
|
main :: IO ()
|
|
main = do
|
|
input <- map (splitOneOf "=,:") . lines <$> readFile "input"
|
|
let sensors = map parse input
|
|
print $ "Cave from to: " ++ show (caveMinMaxX sensors)
|
|
print $ part1 (caveMinMaxX sensors) sensors
|
|
print $ part2 sensors
|
|
|
|
getBorder :: [Sensor] -> [V2 Int]
|
|
getBorder (s:ss) = map (+ fst s) xs ++ getBorder ss
|
|
where
|
|
xs =
|
|
concat $ take 4 $ iterate (map perp) [V2 x (d - x) | x <- [0 .. pred d]]
|
|
d = succ $ dist s
|
|
getBorder [] = []
|
|
|
|
caveMinMaxX :: [Sensor] -> (Int, Int)
|
|
caveMinMaxX sensors = (minimum k, maximum l)
|
|
where
|
|
d = map dist sensors
|
|
s = map (view _y . fst) sensors
|
|
k = zipWith (-) s d
|
|
l = zipWith (+) s d
|
|
|
|
part1 :: (Int, Int) -> [Sensor] -> Int
|
|
part1 (a, b) sensors = length $ filter (== '#') $ map (checkPoint sensors) xs
|
|
where
|
|
xs = [V2 x 2000000 | x <- [a .. b]] --y=10 for testinput
|
|
|
|
part2 :: [Sensor] -> Int
|
|
part2 sensors =
|
|
f $
|
|
head $
|
|
filter (\x -> checkPoint sensors x == ' ') $
|
|
filter (\(V2 x y) -> x >= 0 && x <= 4000000 && y >= 0 && y <= 4000000) $
|
|
getBorder sensors -- <=20 for testinput
|
|
where
|
|
f = (+) <$> view _y <*> ((*) 4000000 . view _x)
|
|
|
|
parse :: [String] -> Sensor
|
|
parse [_, a, _, b, _, c, _, d] = (V2 (read a) (read b), V2 (read c) (read d))
|
|
|
|
checkPoint :: [Sensor] -> V2 Int -> Char
|
|
checkPoint sensors point
|
|
| point `elem` map fst sensors = 'S'
|
|
| point `elem` map snd sensors = 'B'
|
|
| otherwise = checkPoint' sensors point
|
|
where
|
|
checkPoint' (s:ss) p =
|
|
if dist (fst s, p) <= dist s
|
|
then '#'
|
|
else checkPoint' ss p
|
|
checkPoint' [] _ = ' '
|
|
|
|
dist :: Sensor -> Int
|
|
dist (a, b) = sum $ abs $ a - b
|