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Diffstat (limited to '2019/10.hs')
-rw-r--r-- | 2019/10.hs | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/2019/10.hs b/2019/10.hs new file mode 100644 index 0000000..5b6e09c --- /dev/null +++ b/2019/10.hs @@ -0,0 +1,22 @@ +module Main where + +import Data.Array.Unboxed + +import Input + +main :: IO () +main = do + inp <- getInput 10 + let h = length inp + w = length (head inp) + arr = listArray ((0, 0), (w-1, h-1)) (concatMap (map (== '#')) inp) + :: UArray (Int, Int) Bool + asts = map fst (filter snd (assocs arr)) + sight (a,b) (x,y) = + let dx = (x - a) `div` g + dy = (y - b) `div` g + g = gcd (abs (x - a)) (abs (y - b)) + pts = [(a + i * dx, b + i * dy) | i <- [1..g-1]] + in all (not . (arr !)) pts + numVisible p = length (filter (\q -> q /= p && sight p q) asts) + print (maximum (map numVisible asts)) |