This whole prep for interview testing seems very unpleasant and of questionable value to me. Are these interviews in any way representative of day to day operations in the job you are applying for?
I worked as an independent software developer while doing my undergraduate in CS and was very successful just by using fundamentals I learned in courses and then reading and supplementing new things. I then transitioned into a PhD student role in robotics, where I regularly need to come up to speed on topics from all fields of engineering and implement solutions. I love learning and solving problems, but the types of coding interviews discussed seem so far from evaluating that. I produce reliable and novel things I am proud of that take a lot of work, but that would not be enough to pass these interviews.
I know employers need proof of a good fit and competence, but I just dread the day I have to go through one of these things.
Don't worry too much about it. I had the same feeling, since I read HN a lot. Now I'm going through the interview process with several companies and have had a great experience with all of them. Not at all what I expected, based on HN interview threads.
I don't have a CS degree and don't have a clue when it comes to the "rebalance a red-black tree" stuff. In all of my interviews, this hasn't been an issue -- I can think intelligently about problems and solve them, ask questions, and show correct, well-documented, maintainable code that I've written in the past. I'm good with people and with translating between biz problems and tech solutions.
Even in a large tech city (Boston) with lots of well-funded tech companies, my experience has been FAR from the hell you'd imagine from reading HN. I think a lot of this just comes from the SV bubble overrepresented here. And maybe from the huge crowd of people here who, for various reasons, desperately want to get into one of the big 4.
Those few enormous advertising companies (G, F, A, etc.) represent such a small fraction of the actual work out there, and make so much of the noise, that it's hard to keep an accurate perspective.
Anyway, don't worry about it. It sounds like you'll have an easier time than me, and I've had it surprisingly easy during this whole process.
I worked as an independent software developer while doing my undergraduate in CS and was very successful just by using fundamentals I learned in courses and then reading and supplementing new things. I then transitioned into a PhD student role in robotics, where I regularly need to come up to speed on topics from all fields of engineering and implement solutions. I love learning and solving problems, but the types of coding interviews discussed seem so far from evaluating that. I produce reliable and novel things I am proud of that take a lot of work, but that would not be enough to pass these interviews.
I know employers need proof of a good fit and competence, but I just dread the day I have to go through one of these things.