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  1. main :: IO ()
  2. main = interact
  3.      $ (\(base:xs) -> concatMap (allGrays (read base) . read) xs)
  4.      . lines
  5.  
  6. allGrays :: Int -> Int -> String
  7. allGrays base x = unlines $ map eachGray [0..x-1]
  8.   where
  9.     eachGray = concatMap show
  10.              . toGray base
  11.              . toBase base (logB base x)
  12.  
  13. logB :: Int -> Int -> Int
  14. logB base = ceiling . logBase (fromIntegral base) . fromIntegral
  15.  
  16. toBase :: Int -> Int -> Int -> [Int]
  17. toBase base = toBase'
  18.   where
  19.     toBase' :: Int -> Int -> [Int]
  20.     toBase' len 0 = replicate len 0
  21.     toBase' len x = toBase' (len - 1) (x `div` base) ++ [x `mod` base]
  22.  
  23. toGray :: Int -> [Int] -> [Int]
  24. toGray base = toGray' 0
  25.   where
  26.     toGray' :: Int -> [Int] -> [Int]
  27.     toGray' _     []     = []
  28.     toGray' shift (x:xs) = (x + shift) `mod` base : toGray' (shift + base - x) xs
Success #stdin #stdout 0s 8388607KB
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https://ideone.com/3mlo5m
language:
Haskell (ghc 8.4.4)
created:
8 years ago
visibility:
public

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