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adventofcode
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use bitsets

This commit is contained in:
Quinten Kock 2021-12-13 02:32:00 +01:00
parent 27551fcc2f
commit 7f8ce383f9
1 changed files with 14 additions and 11 deletions
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25
2021/day12.hs
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@ -2,7 +2,7 @@ module Day12 where
-- import Data.HashSet (HashSet, member, insert, fromList)
-- import Data.Map ( Map, fromList, unionWith, empty, (!), insert, elems) qualified (map)
import qualified Data.Map as M
import qualified Data.Bits
import Data.Bits ( Bits(shiftL, (.|.), (.&.)) )
import Data.HashSet (HashSet)
import qualified Data.HashSet as S
@ -23,16 +23,19 @@ addPath (from,to) = M.unionWith (++) (M.fromList [(from,[to]), (to,[from])])
isUpper :: Cave -> Bool
isUpper x = x < 0
pathFinder :: System -> Cave -> HashSet Cave -> Int
pathFinder :: System -> Cave -> Int -> Int
pathFinder sys (-1) _ = 1
pathFinder sys x visited = sum $ map (\next -> pathFinder sys next (next `S.insert` visited)) elig
where elig = filter (\cave -> isUpper cave || not (cave `S.member` visited)) (sys M.! x)
pathFinder2 :: System -> Cave -> HashSet Cave -> Int
pathFinder2 sys (-1) _ = 1
pathFinder2 sys x visited = sum $ map (\next -> f next sys next (next `S.insert` visited)) elig
pathFinder sys x visited = sum $ map (\next -> pathFinder sys next (nextmap next)) elig
where
f cave = if isUpper cave || not (cave `S.member` visited) then pathFinder2 else pathFinder
nextmap next = if not (isUpper next) then next .|. visited else visited
elig = filter (\cave -> isUpper cave || (cave .&. visited) == 0) (sys M.! x)
pathFinder2 :: System -> Cave -> Int -> Int
pathFinder2 sys (-1) _ = 1
pathFinder2 sys x visited = sum $ map (\next -> f next sys next (nextmap next)) elig
where
nextmap next = if not (isUpper next) then next .|. visited else visited
f cave = if isUpper cave || (cave .&. visited) == 0 then pathFinder2 else pathFinder
elig = filter (/= 1) (sys M.! x)
convert :: [String] -> M.Map String Int
@ -53,7 +56,7 @@ main = do
let integralSystem = M.mapKeys (conversion M.!) $ M.map (map (conversion M.!)) system
putStrLn "part 1: "
print $ pathFinder integralSystem 1 (S.fromList [1])
print $ pathFinder integralSystem 1 1
putStrLn "part 2: "
print $ pathFinder2 integralSystem 1 (S.fromList [1])
print $ pathFinder2 integralSystem 1 1