I feel like the way I have it is a reasonable, if strictly incorrect, simplification for someone new to the material.
When I write these, I have the newly-hired bootcamp grad as my target audience. Someone who has been taught the basics for how to write code for the web and work as a junior within a company, but has no computer science background. I want them to understand enough to make sense of what they see.
"It's common for an algorithm's performance to depend not just on the size of the input, but also its arrangement. In such cases we typically use big O notation to describe the worst-case scenario. However, note that we may perform similar analysis on the best case or the average case as well."
But here:
> You may sometimes see the Greek letter "theta", Θ, instead of the letter O in big O notation. This is used when the best and worst case have the same order of growth. We can't use it for bubble sort because the best case is O(n) and the worst case is O(n^2).
This is plain false, the worst-case runtime of bubble sort is indeed Θ(n^2). Either delete it, or write about the upper bound / lower bound thing.
I'm struggling to understand how the part about big theta is false. Is the best case for bubble sort not O(n)? I've deleted the section for the time being.
You can talk about the big-O of the average case, the big-theta of the average case, the big-O of the worst case, or the big-theta of the worst case.