I don't know these answers off the top of my head, but if I needed to know them in the real world, I could easily find them out in a couple of seconds or minutes with Google and Wikipedia.
The difference between me and someone who is unfamiliar with computer science (but is still good with Google) is that I can read the answers and their corresponding articles and understand what they mean, as opposed to the other person, who would just be able to recite the answers as trivia.
Actually a few years into the industry, I would doubt any body who claims to know these things straight out of this heart(Unless that is his day job).
Seriously do people remember all this math all the years they are building software? Unless you spend a great deal of time revisiting these concepts every other month, there is no way this is all going to be in your head. And if you actually are spending that amount of time learning this kind of math, I would wonder what kind of a programmer you are. A programmer is supposed to build things in this time, gaining mountains of factual knowledge which doesn't have much value in the real world is not very good use of time.
By the way this algo/DS love looks very similar to tool religion. People focus too much on tools used to solve problem, while they should actually be focused on problems.
Those questions strike me as very basic knowledge. Why would I need to revise constantly to keep that in mind?
And yes, you are right, you can get away without knowing that stuff, and still do awesome work. And you can know all those things, and never get anything done.
The difference between me and someone who is unfamiliar with computer science (but is still good with Google) is that I can read the answers and their corresponding articles and understand what they mean, as opposed to the other person, who would just be able to recite the answers as trivia.