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How should I pronounce the following things? (These are complexities of algorithms.)

  • O(n)
  • O(n*log(n))
  • O(n^2)
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This question is more appropriate for math.stackexchange.com or cstheory.stackexchange.com. – Mitch Jun 1 '11 at 16:28
@Mitch cstheory is for research level questions only, see cstheory.stackexchange.com/faq – Christi Jun 2 '11 at 18:25
I think this is a pointless question. Does OP really want to know whether O is pronounced as Owe rather than Big Oh? Or maybe it should be pronounced zer-OWE? I'm voting to close, and if I could delete it I would do that. – FumbleFingers Jun 23 '11 at 3:06
up vote 15 down vote accepted

Pronunciation would be:

  • order n
  • order n log n
  • order n squared
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If the context (of computational order) is already established, I've also heard "o of n" (etc). – Monica Cellio Jun 1 '11 at 16:38
Its just known as the 'Big O' in my discrete math class. aka the maximum amount of times an algorithm will be run. – OghmaOsiris Jun 23 '11 at 2:56

In the talks I've seen that involve algorithm complexity, I've heard it most often pronounced "oh of n", "oh of n log n", etc.

Mathematicians and CS theorists also use a lowercase o and a capital ϴ for similar measurements with slightly different implications. In this case O( n ) would be pronounced "big oh of n", o( n ) "little oh of n", and ϴ(n) "theta of n".

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That is commonly referred to as Big O Notation, and since my days as a math/CS student I have always pronounced it (and heard it pronounced) as "Big O of n", "Big O of n log n", etc.

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I think it's also common to just say "oh" followed by whatever is inside the parentheses.


There is an "oh n log n" algorithm for that problem

Doesn't that require "oh n squared" time in the worst case?

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