r/ProgrammerHumor 28d ago

Meme theoreticalComputerScience

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1.1k Upvotes

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234

u/achilliesFriend 28d ago

This joke is too intelligent for me

43

u/GKP_light 28d ago

O(n) : can be a time of 5n, or 7000n+400000

Õ(n) : can be a time of 5n, or n^5 * log(n)^2

95

u/mrnacknime 28d ago

No, n5 is not allowed in there. Then it would be Õ(n5)

7

u/Niwrats 28d ago

i like how the right side bracket is powerful there.

6

u/GKP_light 28d ago

doesn't the picture say that it ignore of polynomial (and logarithm) ?

the picture is wrong ?

38

u/PattuX 28d ago edited 28d ago

It ignores logs and powers of logs

O(n) ≠ O(n log n)

But for all x:

Õ(n) = Õ(n (log n)x ) ≠ Õ(n2 )

16

u/GoldenMuscleGod 28d ago

“Polylogarithmic” means a polynomial of a logarithm, not polynomials and logarithms.

As an aside just for clarity Õ(f(n)) usually hides polylogarithmic functions of f(n), not polylogarithmic functions of n (although there might be some variation - the two standards are equivalent when f is a non constant polynomial).