14 lines
309 B
Haskell
14 lines
309 B
Haskell
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gray :: Int -> [[Char]]
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gray n
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| n == 1 = ["0", "1"]
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| n > 1 =
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concatMap
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( \(i, l) ->
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if odd i
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then [(l ++)] <*> ["0", "1"]
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else [(l ++)] <*> ["1", "0"]
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)
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$ zip [1 ..]
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$ gray (n - 1)
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| otherwise = error "Not defined for n<1"
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