23 lines
688 B
Haskell
23 lines
688 B
Haskell
import AoC
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import Data.List (sort)
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import Data.Maybe (fromJust)
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import Numeric (readInt)
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import Text.ParserCombinators.ReadP
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binarify :: String -> Maybe Int
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binarify = oneCompleteResult . readS_to_P $ readInt 2 (`elem` "BFLR") digitValue
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where digitValue 'F' = 0
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digitValue 'B' = 1
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digitValue 'L' = 0
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digitValue 'R' = 1
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findHole :: (Enum a, Eq a) => [a] -> Maybe a
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findHole (x:y:ys) | y == next = findHole $ y:ys
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| otherwise = Just next
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where next = succ x
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findHole _ = Nothing
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main = runAoC (map (fromJust . binarify) . lines) part1 part2
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where part1 = foldr1 max
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part2 = fromJust . findHole . sort
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