AoC/2019/day18/day18.hs

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{-# LANGUAGE LambdaCase #-}
module Main where
import Data.List
import Data.List.Split
import Data.List.Utils
import Data.Char
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import qualified Data.Map.Strict as M
import qualified Data.Set as S
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import Data.Maybe
import Helpers
import Linear.V2
import Debug.Trace
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type DungeonMap = M.Map (V2 Int) Char
data Distance = Reachable Int | Unreachable deriving (Show, Eq)
instance Num Distance where
Reachable x + Reachable y = Reachable (x+y)
Unreachable + _ = Unreachable
_ + Unreachable = Unreachable
instance Ord Distance where
Reachable x <= Reachable y = x<=y
Unreachable <= _ = False
_ <= Unreachable = True
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main :: IO ()
main = do
dMap <- updateScreenBuffer M.empty (0, 0) <$> readFile "testinput1"
putStrLn $ drawMap dMap
print $ distanceFromTo dMap '@' 'f'
print $ distanceFromTo dMap '@' 'a'
print $ distanceFromTo dMap '@' 'A'
print $ tls1 dMap (S.fromList "abcdef") 'f'
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updateScreenBuffer :: DungeonMap -> (Int, Int) -> String -> DungeonMap
updateScreenBuffer buf _ [] = buf
updateScreenBuffer buf (x, y) (a:as) = updateScreenBuffer bufNew coord as
where
bufNew =
if a /= '\n'
then M.insert (V2 x y) a buf
else buf
coord =
if a /= '\n'
then (x + 1, y)
else (0, y + 1)
getNeighbors :: DungeonMap -> V2 Int -> DungeonMap
getNeighbors m coord =
M.fromList
[ (u + coord, M.findWithDefault '#' (u + coord) m)
| u <- unitVecs
, let c = M.findWithDefault '#' (u + coord) m in c `elem` ".@⌂" || isLower c
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]
getNeighborsMap :: DungeonMap -> DungeonMap -> DungeonMap
getNeighborsMap m n = M.unions [getNeighbors m x | (x, _) <- M.toList n]
distanceFromTo :: DungeonMap -> Char -> Char -> Distance
distanceFromTo dMap schar echar =
distanceFromTo' dMap (M.singleton spos schar) spos epos 1
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where
spos = findPos schar dMap
epos = findPos echar dMap
distanceFromTo' mMap nMap start end n
| M.member end newNMap = Reachable n
| newNMap == nMap = Unreachable
| otherwise = distanceFromTo' mMap newNMap start end (n + 1)
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where
newNMap = M.union nMap (getNeighborsMap mMap nMap)
--todo: maek tail recursive
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findPos :: Char -> DungeonMap -> V2 Int
findPos c = head . M.keys . M.filter (`elem` [c])
-- tracePath :: DungeonMap -> Char -> String -> Maybe Int
-- tracePath dMap _ [] = Just 0
-- tracePath dMap c (x:xs) = case distanceFromTo dMap c x of
-- Nothing -> Nothing
-- Just y -> let trace = tracePath dMap c xs in if isJust trace then Just (y + fromJust trace) else Nothing
tls1 :: DungeonMap -> S.Set Char -> Char -> Distance
tls1 dMap nodeSet goal
| S.size nodeSet == 1 = (distanceFromTo dMap '@' (head $ S.toList nodeSet))
-- ^ S = {c}, different 1 element sets possible?
| otherwise =
minimum
[tls1 dMap sMinusC x + distanceFromTo newDMap x goal | x <- S.toList sMinusC]
where
sMinusC = traceShowId (S.delete goal nodeSet)
newDMap = traceShowId (M.insert door '⌂' dMap)
door = traceShowId (findPos (toUpper (traceShowId goal)) dMap)
-- tls2 = undefined