47 lines
1.7 KiB
Haskell
47 lines
1.7 KiB
Haskell
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{-# LANGUAGE BangPatterns #-}
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import Data.List (foldl')
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import Data.List.Split (splitOn)
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import Data.Char (ord, chr)
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import Data.Bits ((.&.))
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import Data.Function ((&))
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import Data.Bimap (Bimap, fromList, toAscList, (!), (!>), insert)
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import qualified Data.Bimap as B (map)
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type Programs = Bimap Int Int
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type Lookup = Programs -> Int -> Int
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type Insert = Int -> Int -> Programs -> Programs
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spin :: Int -> Programs -> Programs
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spin s = B.map (\v -> (v + s) .&. 15)
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swap :: Lookup -> Insert -> Int -> Int -> Programs -> Programs
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swap (!!!) ins keyX keyY bimap =
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ins keyX (bimap !!! keyY) . ins keyY (bimap !!! keyX) $ bimap
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parseMove :: String -> Programs -> Programs
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parseMove str =
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let exchange = swap (!) insert
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partner = swap (!>) insertR
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in case head str of
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's' -> spin . read $ tail str
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'x' -> let x : y : [] = splitOn "/" $ tail str
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in exchange (read x) (read y)
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'p' -> let p : '/' : q : [] = tail str
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in partner (ord p - ord 'a') (ord q - ord 'a')
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where insertR b a = insert a b
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dance :: [Programs -> Programs] -> Programs -> Programs
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dance moves programs = foldl' (&) programs moves
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danceN :: [Programs -> Programs] -> Programs -> Int -> Programs
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danceN _ programs 0 = programs
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danceN moves programs n = let !newPrograms = dance moves programs in danceN moves newPrograms (n-1)
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getOrder :: Programs -> String
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getOrder = map (chr . (+ ord 'a') . snd) . toAscList
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main :: IO ()
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main = do
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moves <- fmap (map parseMove . splitOn ",") $ readFile "16.txt"
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print $ getOrder $ dance moves (fromList $ zip [0..15] [0..15])
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--print $ getOrder $ danceN moves (fromList $ zip [0..15] [0..15]) 1000000000
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