Rather than memorizing a thousand algorithms, I generally focus on being able to solve problems simply, quickly, and elegantly, which will help in actually doing most jobs.
I've heard people actually defend these useless interviews on correlation grounds, like people who are docile, follow the herd, and "prepare" are good hard-working workers who also tend to have done well in school or look polished in other aspects of life. That's what these interviews are really looking for. So, if you're not a well known expert, suck it up, be a servile cog and follow the script.
The trick seems to be knowing when the game is worth playing. There are certainly situations where competition is too fierce and requires too much preparation, so it's not worth doing if you don't really enjoy the game.
I'm not sure getting hired at a large tech firm is quite that competitive, though? They do hire lots of people all the time.
Of course, I could probably come up with a way to do it by myself. I could probably even come up with an efficient way if I spent an afternoon/day on it.
But why do that when I can google it, and get 3 blog posts and 2 stack overflow answers detailing the different options and the trade offs between them, most likely even with an implementation I can base mine off of?
That's why these interview situations are stupid. They're like school where copying is cheating, whereas in real-world situations copying is a great way of doing something.
A lot of resources out there are wrong, inaccurate, or not reasonable for your particular context, and it requires a reasonable amount of algorithmic intelligence to be able to sniff out what's appropriate.
If I had a dollar for every high-upvoted SO post that misstates a problem or doesn't offer proper caveats... but I can make that judgment because I've already thought about a related problem in the past.
It's like asking why one should learn how to write properly when Grammarly and spell checkers exist, or why mental arithmetic is useful when we have calculators—at some point those your tools will be inappropriate or unavailable. Search tools are force multipliers, not replacements for personal knowledge and intuition.
