94 lines
4.9 KiB
Haskell
94 lines
4.9 KiB
Haskell
module Commons where
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import GHC.IO.Handle (isEOF)
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import Data.Map (Map, assocs, member, (!), fromList)
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data Direction = North | East | West | South deriving (Eq, Show)
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data Hole = Hole { direction :: Direction, size :: Int } deriving (Eq, Show)
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type Grid = Map (Int, Int) Hole
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getAllLines :: IO [String]
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getAllLines = do done <- isEOF
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if done then return []
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else do line <- getLine
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otherLines <- getAllLines
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return $ line: otherLines
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parseInstruction :: (Int, Int) -> Direction -> Int -> ((Int, Int), Hole)
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parseInstruction (y, x) South n = ((y + 1, x), Hole {direction = South, size = n - 1})
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parseInstruction (y, x) East n = ((y, x + 1), Hole {direction = East, size = n - 1})
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parseInstruction (y, x) North n = ((y - 1, x), Hole {direction = North, size = n - 1})
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parseInstruction (y, x) West n = ((y, x - 1), Hole {direction = West, size = n - 1})
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parseGrid :: ((Int, Int) -> String -> ((Int, Int), Hole)) ->
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[String] -> [((Int, Int), Hole)] -> Grid
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parseGrid _ [] otherTiles = fromList otherTiles
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parseGrid parseLine (line: t) otherTiles = if null otherTiles then parseGrid parseLine t [parseLine (1, 1) line]
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else let ((y, x), lastHole) = last otherTiles
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newStart = case direction lastHole of
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North -> (y - size lastHole, x)
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East -> (y, x + size lastHole)
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South -> (y + size lastHole, x)
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West -> (y, x - size lastHole)
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tiles = parseLine newStart line
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in parseGrid parseLine t (otherTiles ++ [tiles])
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getBounds :: [((Int, Int), Hole)] -> ((Int, Int), (Int, Int)) -> ((Int, Int), (Int, Int))
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getBounds [] coords = coords
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getBounds (((y, x), h): t) ((yMin, xMin), (yMax, xMax))
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| y < yMin = getBounds (((y, x), h): t) ((y, xMin), (yMax, xMax))
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| x < xMin = getBounds (((y, x), h): t) ((yMin, x), (yMax, xMax))
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| y > yMax = getBounds (((y, x), h): t) ((yMin, xMin), (y, xMax))
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| x > xMax = getBounds (((y, x), h): t) ((yMin, xMin), (yMax, x))
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| otherwise = getBounds t ((yMin, xMin), (yMax, xMax))
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getAreaToStart :: (Int, Int) -> Int -> Hole -> Grid -> Bool -> Int
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getAreaToStart (1, 2) _ _ _ True = 0
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getAreaToStart (1, 0) _ _ _ True = 0
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getAreaToStart (2, 1) _ _ _ True = 0
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getAreaToStart (0, 1) _ _ _ True = 0
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getAreaToStart (y, x) xMax h grid _ | direction h == South =
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let (newY, newX) = (y + size h, x)
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in size h * (xMax - x) +
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if member (newY, newX + 1) grid
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then getAreaToStart (newY, newX + 1) xMax (grid ! (newY, newX + 1)) grid True
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else xMax - x + getAreaToStart (newY, newX - 1) xMax (grid ! (newY, newX - 1)) grid True
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getAreaToStart (y, x) xMax h grid _ | direction h == West =
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let (newY, newX) = (y, x - size h)
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in if member (newY - 1, newX) grid
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then newX - xMax - 1 + getAreaToStart (newY - 1, newX) xMax (grid ! (newY - 1, newX)) grid True
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else getAreaToStart (newY + 1, newX) xMax (grid ! (newY + 1, newX)) grid True
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getAreaToStart (y, x) xMax h grid _ | direction h == North =
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let (newY, newX) = (y - size h, x)
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in size h * (x - xMax - 1) +
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if member (newY, newX + 1) grid
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then x - xMax - 1 + getAreaToStart (newY, newX + 1) xMax (grid ! (newY, newX + 1)) grid True
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else getAreaToStart (newY, newX - 1) xMax (grid ! (newY, newX - 1)) grid True
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getAreaToStart (y, x) xMax h grid _ | direction h == East =
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let (newY, newX) = (y, x + size h)
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in if member (newY - 1, newX) grid
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then getAreaToStart (newY - 1, newX) xMax (grid ! (newY - 1, newX)) grid True
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else xMax - newX + getAreaToStart (newY + 1, newX) xMax (grid ! (newY + 1, newX)) grid True
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getInnerArea :: Grid -> Int
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getInnerArea grid =
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let ((yMin, xMin), (yMax, xMax)) = getBounds (assocs grid) ((maxBound, maxBound), (minBound, minBound))
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in if member (2, 1) grid
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then getAreaToStart (2, 1) xMax (grid ! (2, 1)) grid False
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else if member (1, 2) grid
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then getAreaToStart (1, 2) xMax (grid ! (1, 2)) grid False
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else if member (1, 0) grid
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then getAreaToStart (1, 0) xMax (grid ! (1, 0)) grid False
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else getAreaToStart (0, 1) xMax (grid ! (0, 1)) grid False
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getPerimeter :: Grid -> Int
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getPerimeter = foldr (\ (_, t) -> (+) (size t + 1)) 0 . assocs
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getArea :: Grid -> Int
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getArea grid = let innerArea = getInnerArea grid
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in if innerArea < 0 then abs innerArea
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else innerArea + getPerimeter grid
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