import Data.List import qualified Data.List.Split as S import Debug.Trace addFirst :: [[a]] -> a -> [[a]] addFirst [] x = [[x]] addFirst (y:ys) x = ([x] ++ y) : ys split :: [Char] -> [Char] -> [[Char]] split _ [] = [] split delims (x:xs) | elem x delims = [[]] ++ split delims xs | otherwise = addFirst (split delims xs) x splitInput :: String -> [String] splitInput = split ['\n'] solve1 :: [String] -> Int solve1 x = sum $ map (\x -> length x -1) $ map (S.splitOn "XMAS") $ rowsColumnsDiags x solve2 :: [String] -> Int 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 rowsColumnsDiags :: [String] -> [String] 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)]) getLeadDiag :: [[a]] -> Int -> [a] getLeadDiag [] _ = [] getLeadDiag (x:xs) y | y < 0 = getLeadDiag xs (y+1) | y >= length x = [] | otherwise = [x!!y] ++ getLeadDiag xs (y+1) addIndexes2 :: [[a]] -> [[(a, Int, Int)]] addIndexes2 xs = map (\x -> map (\y -> ((xs!!x)!!y, x, y)) [0..(length (xs!!x) -1)]) [0..(length xs-1)] main :: IO() main = do fileinp <- readFile "input.txt" let parsed = splitInput fileinp let solved1 = solve1 parsed let solved2 = solve2 parsed print solved1 print solved2