35 lines
1.4 KiB
Haskell
35 lines
1.4 KiB
Haskell
import Data.List
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addFirst :: [[a]] -> a -> [[a]]
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addFirst [] x = [[x]]
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addFirst (y:ys) x = ([x] ++ y) : ys
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split :: [Char] -> String -> [String]
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split _ [] = []
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split delims (x:xs)
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| elem x delims = [[]] ++ split delims xs
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| otherwise = addFirst (split delims xs) x
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splitInput :: String -> [((Int, Int), Char)]
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splitInput text = concat $ map (\(x, zs) -> map (\(y, z) -> ((x, y), z)) zs) $ map (\(x, zs) -> (x, filter (\(_, z) -> z /= '.') zs)) $ indexed $ map indexed $ split ['\n'] text
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indexed :: [a] -> [(Int, a)]
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indexed xs = zip [0..((length xs)-1)] xs
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checkBounds :: (Num a, Ord a) => (a, a) -> (a, a) -> Bool
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checkBounds (c, d) (a, b) = (0 <= a) && (0 <= b) && (a < c) && (b < d)
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solve1 :: [((Int, Int), Char)] -> Int
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solve1 xs = length $ nub $ filter (checkBounds (50, 50)) $ concat $ concat $ map (\((x0, y0), a) -> map (\((x1, y1), b) -> if (a==b && ((x0, y0) /= (x1, y1))) then [(x0+x0-x1, y0+y0-y1), (x1+x1-x0, y1+y1-y0)] else []) xs) xs
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solve2 :: [((Int, Int), Char)] -> Int
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solve2 xs = length $ nub $ filter (checkBounds (50, 50)) $ concat $ concat $ concat $ map (\((x0, y0), a) -> map (\((x1, y1), b) -> if a==b then (map (\n -> [(x0+n*(x0-x1), y0+n*(y0-y1)), (x1+n*(x1-x0), y1+n*(y1-y0))]) [1..50]) else []) xs) xs
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main :: IO()
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main = do
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fileinp <- readFile "input.txt"
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let parsed = splitInput fileinp
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let solved1 = solve1 parsed
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let solved2 = solve2 parsed
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print solved1
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print solved2
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