19 lines
512 B
Haskell
19 lines
512 B
Haskell
import Data.Bifunctor (first)
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import Data.List (mapAccumL)
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import Data.Tuple (swap)
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roman :: Int -> String
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roman =
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romanFromInt $
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zip
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[1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]
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(words "M CM D CD C XC L XL X IX V IV I")
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romanFromInt :: [(Int, String)] -> Int -> String
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romanFromInt nks n = concat . snd $ mapAccumL go n nks
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where
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go a (v, s) = swap $ first ((>> s) . enumFromTo 1) $ quotRem a v
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main :: IO ()
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main = (putStrLn . unlines) (roman <$> [1666, 1990, 2008, 2016, 2018])
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