29 lines
943 B
Haskell
29 lines
943 B
Haskell
import qualified Data.Map as M
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import Data.List.Split
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import Control.Arrow
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import Control.Monad
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main :: IO ()
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main = do
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input <- map (map read . filter (/="->")) <$> map (splitOneOf ", ") <$> lines <$> readFile "input"
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let process = length . M.filter (> 1) . M.fromListWith (+) . toMap
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print $ join (***) process $ (filterOrth input,input)
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filterOrth :: [[Int]] -> [[Int]]
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filterOrth [] = []
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filterOrth ([x1,y1,x2,y2]:ss)
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| x1==x2 || y1==y2 = [x1,y1,x2,y2]:filterOrth ss
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| otherwise = filterOrth ss
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toMap :: [[Int]] -> [((Int,Int),Int)]
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toMap [] = []
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toMap ([x1,y1,x2,y2]:xs)
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| y1==y2 = zip ySame (repeat 1) ++ toMap xs
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| x1==x2 = zip xSame (repeat 1) ++ toMap xs
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| otherwise = zip diag (repeat 1) ++ toMap xs
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where diag = zip xRange yRange
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ySame = zip xRange (repeat y1)
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xSame = zip (repeat x1) yRange
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xRange = [x1,x1-(signum $ x1-x2)..x2]
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yRange = [y1,y1-(signum $ y1-y2)..y2]
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