63 lines
2.3 KiB
Haskell
63 lines
2.3 KiB
Haskell
module Day12 where
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-- import Data.HashSet (HashSet, member, insert, fromList)
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-- import Data.Map ( Map, fromList, unionWith, empty, (!), insert, elems) qualified (map)
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import qualified Data.Map as M
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import Data.Bits ( Bits(shiftL, (.|.), (.&.)) )
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import Data.HashSet (HashSet)
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import qualified Data.HashSet as S
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import Data.List.Split (splitOn)
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import qualified Data.Char
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type Cave = Int
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type Path = (Cave,Cave)
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type System = M.Map Cave [Cave]
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readPath :: String -> (String,String)
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readPath s = (from,to) where [from,to] = splitOn "-" s
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addPath :: (String,String) -> M.Map String [String] -> M.Map String [String]
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addPath (from,to) = M.unionWith (++) (M.fromList [(from,[to]), (to,[from])])
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isUpper :: Cave -> Bool
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isUpper x = x < 0
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pathFinder :: System -> Cave -> Int -> Int
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pathFinder sys (-1) _ = 1
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pathFinder sys x visited = sum $ map (\next -> pathFinder sys next (nextmap next)) elig
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where
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nextmap next = if not (isUpper next) then next .|. visited else visited
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elig = filter (\cave -> isUpper cave || (cave .&. visited) == 0) (sys M.! x)
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pathFinder2 :: System -> Cave -> Int -> Int
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pathFinder2 sys (-1) _ = 1
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pathFinder2 sys x visited = sum $ map (\next -> f next sys next (nextmap next)) elig
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where
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nextmap next = if not (isUpper next) then next .|. visited else visited
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f cave = if isUpper cave || (cave .&. visited) == 0 then pathFinder2 else pathFinder
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elig = filter (/= 1) (sys M.! x)
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convert :: [String] -> M.Map String Int
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convert caves = conversion
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where
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(conversion, numhi, numlo) = foldr go (M.fromList [("end", -1), ("start", 1)], 2, 1) caves
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go cave (map,upper,lower)
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| cave `M.member` map = (map,upper,lower)
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| Data.Char.isUpper (head cave) = (M.insert cave (-upper) map, upper+1, lower)
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| otherwise = (M.insert cave (1 `Data.Bits.shiftL` lower) map, upper, lower+1)
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main :: IO ()
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main = do
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input <- map readPath . lines <$> getContents
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let system = foldr addPath M.empty input
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let conversion = convert $ concat $ M.elems system
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print conversion
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let integralSystem = M.mapKeys (conversion M.!) $ M.map (map (conversion M.!)) system
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putStrLn "part 1: "
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print $ pathFinder integralSystem 1 1
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putStrLn "part 2: "
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print $ pathFinder2 integralSystem 1 1
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