AoC Day 4 https://adventofcode.com/2021/day/4

aoc_day4.hs

import Data.List.Split(splitOn)

isWin :: [[Maybe Integer]] -> Bool

isWin xs = any isWin1 [xs, revertMatrix xs []] where
     revertMatrix [] newMat = newMat
     revertMatrix xs newMat = revertMatrix (filter (\y -> length y > 0) (map tail xs)) (newMat ++ [map head xs])


isWin1 [] = False
isWin1 (x:xs) | complete x = True
             | otherwise = isWin1 xs
             where
              complete [] = True
              complete ((Nothing):xs) = complete xs
              complete ((Just _):_) = False

getSum :: [[Maybe Integer]] -> Integer
getSum [] = 0
getSum (x:xs) = getS x + getSum xs where
        getS [] = 0
        getS ((Nothing):xs) = getS xs
        getS ((Just i):xs) = i + getS xs

getCard x xs = (getCardRow x) : xs
getCardRow x = map (\y -> Just (read y :: Integer)) (words x)

parseCards [] [] cards = cards
parseCards [] card cards = card:cards

parseCards ("":xs) [] cards = parseCards xs [] cards
parseCards ("":xs) card cards = parseCards xs [] (card:cards)

parseCards (current:xs) card cards = parseCards xs (getCard current card) cards


addNumber :: Integer -> [[Maybe Integer]] -> [[Maybe Integer]]
addNumber _ [] = []
addNumber n (x:xs) = (checkerNumber x n):(addNumber n xs) where
    checkerNumber [] _ = []
    checkerNumber (a@(Just x):xs) n | x == n = Nothing:(checkerNumber xs n)
                                    | otherwise = a:(checkerNumber xs n)
    checkerNumber (x:xs) n = x:(checkerNumber xs n)

play1 _ [] = Nothing
play1 xs (n:nx) | any isWin (map (addNumber n) xs) = getResult (map (addNumber n) xs) n
               | otherwise = play1 (map (addNumber n) xs) nx
         where
           getResult (x:xs) n | isWin x  = Just (n * (getSum x))
                              | otherwise =  getResult xs n

play2 [x] (n:_) = Just (n * (getSum (addNumber n x)))
play2 xs (n:nx) = play2 (filter (\y -> not $ isWin y) (map (addNumber n) xs)) nx



part1 (x:xs) = play1 (parseCards xs [] []) (getNums x)
part2 (x:xs) = play2 (parseCards xs [] []) (getNums x)



getNums x = map (\y -> read y :: Integer) (splitOn "," x)

solve :: String -> IO ()
solve filename = do
  c <- readFile filename
  print $ part1 (lines c)
  print $ part2 (lines c)

main = solve "input.txt"