24 lines
463 B
Haskell
24 lines
463 B
Haskell
{-# LANGUAGE NumericUnderscores #-}
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module Roman (solution) where
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solution :: String -> Int
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solution = sum . mergeParts . map fromRoman
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mergeParts :: [Int] -> [Int]
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mergeParts [] = []
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mergeParts [n1] = [n1]
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mergeParts (n1:n2:rest)
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| n1 < n2 = n2 - n1 : mergeParts rest
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| otherwise = n1 : mergeParts (n2:rest)
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fromRoman :: Char -> Int
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fromRoman c = case c of
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'I' -> 1
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'V' -> 5
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'X' -> 10
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'L' -> 50
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'C' -> 100
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'D' -> 500
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'M' -> 1_000
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_ -> 0
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