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import Data.List
import Data.List.Split
type Vec = (Int, Int)
type Robot = (Vec, Vec)
size :: Vec
size = (101, 103)
mul :: Int -> Vec -> Vec
mul s (x, y) = (s*x, s*y)
add :: Vec -> Vec -> Vec
add (x, y) (z, w) = (x+z, y+w)
clamp :: Vec -> Vec -> Vec
clamp m@(mx, my) v@(x, y)
| x < 0 = clamp m (x + mx, y)
| y < 0 = clamp m (x, y + my)
| x >= mx = clamp m (x - mx, y)
| y >= my = clamp m (x, y - my)
| otherwise = v
consume1 :: String -> Robot
consume1 str =
((atoi px, atoi py), (atoi vx, atoi vy))
where
atoi = (read::String->Int)
["p", px, py, "v", vx, vy] = splitOneOf "=, " str
consume :: String -> [Robot]
consume file =
map consume1 $ lines file
step :: [Robot] -> [Robot]
step robots =
map stepOne robots
where
stepOne (p, v) = (clamp size $ add p v, v)
applyN :: Int -> (a -> a) -> a -> a
applyN n f =
foldr (.) id (replicate n f)
count :: Vec -> Vec -> [Robot] -> Int
count tl br robots =
length $ filter (inside tl br) robots
where
inside (xs, ys) (xe, ye) ((x, y), _) =
x >= xs && x < xe && y >= ys && y < ye
counts :: [Robot] -> (Int, Int, Int, Int)
counts robots =
(count (0, 0) (tx, ty) robots,
count ((tx + 1), 0) (mx, ty) robots,
count (0, (ty + 1)) (tx, my) robots,
count ((tx + 1), (ty + 1)) (mx, my) robots)
where
(mx, my) = size
tx = (mx - 1) `div` 2
ty = (my - 1) `div` 2
safety :: (Int, Int, Int, Int) -> Int
safety (a, b, c, d) =
a * b * c * d
part1 :: [Robot] -> Int
part1 robots =
safety $ counts $ applyN 100 step robots
main = do
file <- readFile "day14.input"
let robots = consume file
putStrLn ("Part 1: " ++ (show $ part1 robots))
--putStrLn ("Part 2: " ++ (show $ part2 robots))
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