24 lines
687 B
Haskell
24 lines
687 B
Haskell
import Data.List (isPrefixOf, transpose)
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import Data.Universe.Helpers (diagonals)
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countTimes :: String -> String -> Int
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countTimes _ [] = 0
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countTimes s fullLine@(_:nextLine)
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| s `isPrefixOf` fullLine = 1 + countTimes s (drop (length s) fullLine)
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| otherwise = countTimes s nextLine
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countHoriz :: String -> Int
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countHoriz l = countTimes "XMAS" l + countTimes "SAMX" l
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countLines :: [String] -> Int
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countLines = sum . map countHoriz
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countAll :: [String] -> Int
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countAll ls = countLines ls
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+ countLines (transpose ls)
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+ countLines (diagonals ls)
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+ countLines (diagonals (reverse ls))
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main :: IO ()
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main = print . countAll . lines =<< readFile "data.txt"
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