44 lines
1.8 KiB
Haskell
44 lines
1.8 KiB
Haskell
import Data.List
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import qualified Data.List.Split as S
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import Debug.Trace
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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] -> [Char] -> [[Char]]
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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 -> [String]
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splitInput = split ['\n']
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solve1 :: [String] -> Int
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solve1 x = sum $ map (\x -> length x -1) $ map (S.splitOn "XMAS") $ rowsColumnsDiags x
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solve2 :: [String] -> Int
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solve2 xs = length $ filter (\(x, y, z) -> (xs!!(y-1)!!(z+1) == 'M' && xs!!(y+1)!!(z-1) == 'S') || (xs!!(y-1)!!(z+1) == 'S' && xs!!(y+1)!!(z-1) == 'M')) $ filter (\(x, y, z) -> x == 'A' && ((xs!!(y-1)!!(z-1) == 'M' && xs!!(y+1)!!(z+1) == 'S') || (xs!!(y-1)!!(z-1) == 'S' && xs!!(y+1)!!(z+1) == 'M'))) $ concat $ map (drop 1) $ map (\x -> take (length x -1) x) $ drop 1 $ take (length xs - 1) $ addIndexes2 xs
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rowsColumnsDiags :: [String] -> [String]
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rowsColumnsDiags x = x ++ (map reverse x) ++ (transpose x) ++ (map reverse (transpose x)) ++ (map (getLeadDiag x) [(-length x)..(length x)]) ++ (map (getLeadDiag (reverse x)) [(-length x)..(length x)]) ++ map reverse (map (getLeadDiag x) [(-length x)..(length x)]) ++ map reverse (map (getLeadDiag (reverse x)) [(-length x)..(length x)])
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getLeadDiag :: [[a]] -> Int -> [a]
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getLeadDiag [] _ = []
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getLeadDiag (x:xs) y
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| y < 0 = getLeadDiag xs (y+1)
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| y >= length x = []
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| otherwise = [x!!y] ++ getLeadDiag xs (y+1)
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addIndexes2 :: [[a]] -> [[(a, Int, Int)]]
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addIndexes2 xs = map (\x -> map (\y -> ((xs!!x)!!y, x, y)) [0..(length (xs!!x) -1)]) [0..(length xs-1)]
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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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