44 lines
1.2 KiB
Haskell
44 lines
1.2 KiB
Haskell
import Data.HashMap (Map, alter, empty, findWithDefault, elems)
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data Instruction = I {
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reg :: String,
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val :: Int,
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src :: String,
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fnc :: Int -> Bool
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}
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getFnc :: String -> (Int -> Int -> Bool)
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getFnc s = case s of
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"<" -> (<)
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"<=" -> (<=)
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">" -> (>)
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">=" -> (>=)
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"==" -> (==)
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"!=" -> (/=)
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addToMaybe :: Int -> Maybe Int -> Maybe Int
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addToMaybe i (Just x) = Just $ i + x
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addToMaybe i Nothing = Just i
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parseLine :: String -> Instruction
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parseLine s =
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let (register : operation : value : _ : source : function : argument : _) = words s
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in I {
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reg = register,
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val = case operation of
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"inc" -> read value
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"dec" -> (- read value),
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src = source,
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fnc = flip (getFnc function) $ read argument
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}
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executeInstruction :: Map String Int -> Instruction -> Map String Int
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executeInstruction m (I r v s f) =
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alter (addToMaybe . (*v) . fromEnum . f $ findWithDefault 0 s m) r m
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main :: IO ()
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main = do
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input <- readFile "8.txt"
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let maxima = map (maximum . elems) . tail . scanl executeInstruction empty . map parseLine . lines $ input
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print $ last maxima
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print $ maximum maxima |