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[hs] Clean up 2020_17

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This commit is contained in:
Joscha 2020-12-18 17:23:50 +00:00
parent 759ce027ab
commit ca9e4c7bf1
1 changed files with 10 additions and 16 deletions
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26
hs/src/Aoc/Y2020/D17.hs
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@ -22,11 +22,7 @@ newWorld dims slice = Set.fromList $ do
pure $ [x, y] ++ replicate (dims - 2) 0
vicinity :: Pos -> [Pos]
vicinity [] = [[]]
vicinity (x:xs) = do
x2 <- [x - 1, x, x + 1]
xs2 <- vicinity xs
pure $ x2 : xs2
vicinity = foldr (\x -> ((:) <$> [x - 1, x, x + 1] <*>)) (pure [])
neighbours :: Pos -> [Pos]
neighbours p = [p2 | p2 <- vicinity p, p2 /= p]
@ -35,27 +31,25 @@ interesting :: World -> Set.Set Pos
interesting w = Set.fromList $ vicinity =<< Set.toList w
alive :: Bool -> Int -> Bool
alive True 2 = True
alive True 3 = True
alive False 3 = True
alive _ _ = False
alive True 2 = True
alive _ 3 = True
alive _ _ = False
step :: World -> World
step w = Set.filter go $ interesting w
where
go p = alive (p `Set.member` w) (length $ filter (`Set.member` w) $ neighbours p)
step w = flip Set.filter (interesting w) $ \p ->
alive (p `Set.member` w) (length $ filter (`Set.member` w) $ neighbours p)
steps :: World -> World
steps = foldr (.) id $ replicate 6 step
steps :: Int -> World -> World
steps n = foldr (.) id $ replicate n step
solver :: [[Bool]] -> IO ()
solver slice = do
putStrLn ">> Part 1"
print $ Set.size $ steps $ newWorld 3 slice
print $ Set.size $ steps 6 $ newWorld 3 slice
putStrLn ""
putStrLn ">> Part 2"
print $ Set.size $ steps $ newWorld 4 slice
print $ Set.size $ steps 6 $ newWorld 4 slice
day :: Day
day = dayParse parser solver