30 lines
848 B
Haskell
30 lines
848 B
Haskell
data Hand = Rock | Paper | Scissor deriving (Eq,Enum,Bounded,Show)
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instance Ord Hand where
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compare x y = case fromEnum x - fromEnum y `mod` 3 of
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0 -> EQ
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1 -> GT
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(-2) -> GT
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_ -> LT
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(+.) :: Hand -> Int -> Hand
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(+.) a b = toEnum $ flip mod 3 $ (+) (fromEnum a) b
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main :: IO ()
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main = do
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input <- map (concat . words) . lines <$> readFile "input"
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print $ day2 id input
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print $ day2 realStrat input
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toHands :: [Char] -> [Hand]
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toHands x = map toEnum $ (zipWith subtract [65,88]) (map fromEnum x)
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realStrat :: [Hand] -> [Hand]
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realStrat (a:b:[]) = [a,a +. fromEnum (b +. 2)]
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day2 :: ([Hand] -> [Hand]) -> [[Char]] -> Int
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day2 f = sum . map (play . f . toHands)
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play :: [Hand] -> Int
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play (x:y:[]) = fromEnum y + 1 + if x == y then 3 else fromEnum (x<y) * 6
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