38 lines
1.0 KiB
Haskell
38 lines
1.0 KiB
Haskell
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type Race = (Int, Int)
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loadRaces :: String -> [Race]
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loadRaces str = zip ts ds
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where
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[ts, ds] = map getNs $ splitStr '\n' str
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getNs :: String -> [Int]
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getNs = map read . filter (not . null) . splitStr ' ' . drop 2 . dropWhile (/=':')
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loadRace :: String -> Race
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loadRace str = (t, d)
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where
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[t, d] = map getN $ splitStr '\n' str
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getN :: String -> Int
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getN = read . filter (/= ' ') . drop 2 . dropWhile (/= ':')
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splitStr :: Char -> String -> [String]
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splitStr onC = foldr splitStr' [""]
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where
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splitStr' :: Char -> [String] -> [String]
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splitStr' c (cur:splits)
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| c == onC = "":cur:splits
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| otherwise = (c:cur):splits
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raceOptions :: Race -> Int
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raceOptions (t, d) = t + 1 - 2 * head [n | n <- [0..t], n * (t-n) > d]
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part1 :: String -> String
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part1 = show . product . map raceOptions . loadRaces
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part2 :: String -> String
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part2 = show . raceOptions . loadRace
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main :: IO ()
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main = do
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s <- readFile "input.txt"
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putStrLn $ "Part 1: " ++ part1 s
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putStrLn $ "Part 2: " ++ part2 s
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