day 14

14/solution.hs

@@ -0,0 +1,47 @@
+import Data.List
+import Data.Maybe
+import Debug.Trace
+
+traceOut :: Show a => a -> a
+traceOut x = (traceShow x x)
+
+addFirst :: [[a]] -> a -> [[a]]
+addFirst [] x = [[x]]
+addFirst (y:ys) x = ([x] ++ y) : ys
+
+split :: [Char] -> String -> [String]
+split _ [] = []
+split delims (x:xs)
+  | elem x delims = [[]] ++ split delims xs
+  | otherwise     = addFirst (split delims xs) x
+
+toTuple :: [a] -> Maybe (a, a)
+toTuple [] = Nothing
+toTuple (_:[]) = Nothing
+toTuple (x:y:_) = Just (x, y)
+
+splitInput :: String -> [((Int, Int), (Int, Int))]
+splitInput = map (fromJust . toTuple . map (fromJust . toTuple . map read . tail . split "=,")) . map (split " ") . split "\n"
+
+solve1 :: [((Int, Int), (Int, Int))] -> Int
+solve1 = quadrants (101, 103) . map (\(x, y) -> (x `mod` 101, y `mod` 103)) . map (\((x, y), (vx, vy)) -> (x + 100*vx, y+100*vy))
+
+quadrants :: (Int, Int) -> [(Int, Int)] -> Int
+quadrants (x, y) pos = (length $ filter (\(a, b) -> (a < x `div` 2) && (b < y `div` 2)) pos) *
+                       (length $ filter (\(a, b) -> (a < x `div` 2) && (b > y `div` 2)) pos) *
+                       (length $ filter (\(a, b) -> (a > x `div` 2) && (b > y `div` 2)) pos) *
+                       (length $ filter (\(a, b) -> (a > x `div` 2) && (b < y `div` 2)) pos)
+
+solve2 :: Int -> [((Int, Int), (Int, Int))] -> String
+solve2 n = concat . map ((\x -> x ++ "\n") . concat . map (\x -> if x>0 then show x else " ")) . (\pos -> map (\row -> map (\col -> length $ filter (==(col, row)) pos) [0..100]) [0..102]) . map (\(x, y) -> (x `mod` 101, y `mod` 103)) . map (\((x, y), (vx, vy)) -> (x + n*vx, y+n*vy))
+
+iter = 7572
+
+main :: IO()
+main = do
+       fileinp <- readFile "input.txt"
+       let parsed = splitInput fileinp
+       let solved1 = solve1 parsed
+       let solved2 = solve2 iter parsed
+       print solved1
+       putStrLn solved2