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September 2017 Update

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Ingy döt Net 2017-09-23 10:01:46 +02:00
parent bba7bfd280
commit ba8067c3b7
14570 changed files with 153136 additions and 63871 deletions
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26
Task/Roman-numerals-Encode/Haskell/roman-numerals-encode-1.hs
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@ -1,13 +1,23 @@
digit :: Char -> Char -> Char -> Integer -> String
digit x y z k =
[[x],[x,x],[x,x,x],[x,y],[y],[y,x],[y,x,x],[y,x,x,x],[x,z]] !!
[[x], [x, x], [x, x, x], [x, y], [y], [y, x], [y, x, x], [y, x, x, x], [x, z]] !!
(fromInteger k - 1)
toRoman :: Integer -> String
toRoman 0 = ""
toRoman x | x < 0 = error "Negative roman numeral"
toRoman x | x >= 1000 = 'M' : toRoman (x - 1000)
toRoman x | x >= 100 = digit 'C' 'D' 'M' q ++ toRoman r where
(q,r) = x `divMod` 100
toRoman x | x >= 10 = digit 'X' 'L' 'C' q ++ toRoman r where
(q,r) = x `divMod` 10
toRoman x = digit 'I' 'V' 'X' x
toRoman x
| x < 0 = error "Negative roman numeral"
toRoman x
| x >= 1000 = 'M' : toRoman (x - 1000)
toRoman x
| x >= 100 = digit 'C' 'D' 'M' q ++ toRoman r
where
(q, r) = x `divMod` 100
toRoman x
| x >= 10 = digit 'X' 'L' 'C' q ++ toRoman r
where
(q, r) = x `divMod` 10
toRoman x = digit 'I' 'V' 'X' x
main :: IO ()
main = print $ toRoman <$> [1999, 25, 944]