Day 3: Lobby

Megathread guidelines

  • Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
  • You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL

FAQ

  • Amy@piefed.blahaj.zoneEnglish
    1·
    1 month ago

    Version 2. I realized last night that my initial approach was way more complicated than it needed to be…

    import Data.List
import Data.Semigroup

maxJolt :: Int -> [Char] -> Int
maxJolt r xs = read $ go r (length xs) xs
  where
    go r n xs =
      (\(Arg x xs) -> x : xs) . maximum $
        do
          (n', x : xs') <- zip (reverse [r .. n]) (tails xs)
          return . Arg x $ if r == 1 then [] else go (r - 1) (n' - 1) xs'

main = do
  input <- lines <$> readFile "input03"
  mapM_ (print . sum . (`map` input) . maxJolt) [2, 12]