aoc2021/app/D4P1.hs

module Main where

import Data.List.Split (chunksOf, splitOn)
import Debug.Trace (traceShowId)
import Data.List (transpose)

main :: IO ()
main = interact solution

type Board = [(Bool, Int)]

second :: (b -> c) -> (a, b) -> (a, c)
second f (a, b) = (a, f b)
second2 :: (a -> b -> c) -> (a, b) -> (a, c)
second2 f (a, b) = (a, f a b)

first :: (a -> c) -> (a, b) -> (c, b)
first f (a, b) = (f a, b)

solution :: String -> String
solution = show
         . second2 applydraws
         . second ( chunksOf 25
                  . zip (repeat False)
                  . map (read :: String -> Int)
                  . concatMap words
                  )
         . first ( map (read :: String -> Int)
                 . splitOn ","
                 )
         . (\x -> (head x, tail x))
         . lines

select :: Int -> Board -> Board
select n = map (\(d, p) -> ((n == p) || d, p))

hasWon :: Board -> Bool
hasWon b = any and r || any and (transpose r)
  where r = chunksOf 5 (map fst b)

score :: Int -> Board -> Int
score lastn b = lastn * boardleft b
  where boardleft = sum . map snd . filter (not . fst)

applydraw :: Int -> [Board] -> [Board]
applydraw n = map (select n)

applydraws ::[Int] -> [Board] -> [(Int, [Board])]
applydraws []     _ = []
applydraws (n:ns) b = (n, nb) : applydraws ns nb
  where
    nb = applydraw n b

getWinning :: [[Board]] -- ^ Mapped boards
           -> Board
getWinning [] = error "WTF"
getWinning (bs:r) = if any hasWon bs then getWinning' bs else getWinning r
  where
    getWinning' :: [Board] -> Board
    getWinning' (b:bs)
      | hasWon b = b
      | otherwise = getWinning' bs
    getWinning' [] = error "Wtf"