80 lines
1.7 KiB
Haskell
80 lines
1.7 KiB
Haskell
import System.IO
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import Data.List
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import Data.List.Split
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parseForest :: String -> [[Int]]
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parseForest = map (\ r -> map toInt r) . lines
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where toInt = (\ c -> read [c] :: Int)
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rotateForest :: Int -> [[a]] -> [[a]]
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rotateForest 0 f = f
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rotateForest 1 f = transpose f
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rotateForest 2 f = map reverse f
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rotateForest 3 f = map reverse $ transpose f
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rotateForestBack 3 f = transpose $ map reverse f
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rotateForestBack n f = rotateForest n f
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visibilityRow :: Int -> [Int] -> [Bool]
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visibilityRow _ [] = []
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visibilityRow m (x:xs)
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| x == 9 = (True:[False | _ <- xs])
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| x > m = (True:visibilityRow x xs)
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| otherwise = (False:visibilityRow m xs)
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visibilityMap :: [[Int]] -> [[Bool]]
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visibilityMap = map (visibilityRow (-1))
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merge' :: (a -> a -> a) -> [[[a]]] -> [[a]]
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merge' f = foldl1 (zipWith (zipWith f))
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merge :: (a -> a -> a) -> [[[a]]] -> [[a]]
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merge f m = merge' f $ zipWith rotateForestBack [0..length m] m
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count :: [[Bool]] -> Int
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count = length . filter (==True) . concat
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hv :: [[Int]] -> Int
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hv [left,[c],right] = (v $ reverse left) * (v right)
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where
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v [] = 0
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v (x:xs)
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| x >= c = 1
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| otherwise = 1 + (v xs)
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hvm :: [[Int]] -> [[Int]]
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hvm = map (map hv . splits)
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where
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splits a = map (\n -> splitPlacesBlanks [n,1,length a] a) [0..length a-1]
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handler :: String -> String
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handler s = (show visibleTrees) ++ "\n" ++
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(show hvs) ++ "\n"
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where
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f = parseForest s
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dirs = map (\ x -> rotateForest x f) [0..3]
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visibleTrees = count $ merge (||) $ map visibilityMap dirs
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hvs = maximum $ concat $ merge (*) $ map hvm (take 2 dirs)
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main :: IO ()
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main = do
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interact handler
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