aoc-2021-22

Aoc2021Prob22.hs

{-# LANGUAGE NamedFieldPuns #-}
module Aoc2021Prob22 where

import Data.Bifunctor (bimap)
import Data.Maybe (fromJust)
import Text.Read (readMaybe)

data SpecLine = SpecLine
  { state :: State
  , cuboid :: Cuboid
  }
  deriving (Show)

addSpecLine :: SpecLine -> SpecLine -> (SpecLine, SpecLine)
addSpecLine SpecLine { state, cuboid } _ = _

intersectionRange :: Range -> Range -> Maybe Range
intersectionRange Range { start = s1, end = e1 } Range { start = s2, end = e2 } =
  if (s2 <= e1 && e1 <= e2) || (s1 <= e2 && e2 <= e1)
  then Just (Range { start = max s1 s2, end = min e1 e2 })
  else Nothing

-- Expect this intersection to be empty
-- --------xxxx-------xxxx-----
--        (-1, 0)     (9, 11)

-- Expect this to be (-1, 0)
-- --------xxxyyxx-----
--     (-3, 0) (-1, 2)

maxRange :: Range
maxRange = Range
  { start = -50
  , end = 50
  }

intersectionCuboid :: Cuboid -> Cuboid -> Maybe Cuboid
intersectionCuboid Cuboid {x = x1, y = y1, z = z1} Cuboid {x = x2, y = y2, z = z2} =
  Cuboid
  <$> intersectionRange x1 x2
  <*> intersectionRange y1 y2
  <*> intersectionRange z1 z2

data State
  = On
  | Off
  deriving (Show)

data Cuboid = Cuboid
  { x :: Range
  , y :: Range
  , z :: Range
  }
  deriving (Show)

data Range = Range
  { start :: Int
  , end :: Int
  }
  deriving (Show)

main :: IO ()
main = do
  ls <- map makeSpecLine . lines <$> readFile "./aoc-2021-problem-22-input.txt"

  print ls

makeSpecLine :: String -> SpecLine
makeSpecLine specLineStr =
  SpecLine
    { state = getState state'
    , cuboid = getCuboid cuboid'
    }
  where
  (state', _:cuboid') = break (== ' ') specLineStr

getState :: String -> State
getState "on" = On
getState _    = Off

getCuboid :: String -> Cuboid
getCuboid cs =
  makeCuboid $ lines $ map (\c -> if c == ',' then '\n' else c) cs
  where
    makeCuboid :: [String] -> Cuboid
    makeCuboid [x, y, z] =
      Cuboid
        { x = parseRange x
        , y = parseRange y
        , z = parseRange z
        }

parseRange :: String -> Range
parseRange s = Range { start, end }
  where
  (start, end) =
    bimap read read
      $ fmap (drop 2)
      $ break (== '.')
      $ snd
      $ fmap tail
      $ break (== '=') s