I just finished reading Bill Kilday's Never Lost Again. It was amazing that four engineers produced the ground-breaking Google Maps in 16 months. Algorithm/Math questions used to be really effective at finding engineerings like those four engineers. There was a reason that Microsoft resorted to algorithm puzzles in its hay days as well.

It's just unfortunate that there's so much prepping materials online nowadays that the programming puzzles have become ineffective. It gets worse as many interviewers were not good enough to ask follow-up questions. For instance, addition with big integers is a pretty easy interview question, right? But if a candidate can go as deep as this article: https://bearssl.org/bigint.html, I can be pretty confident that the candidate is really really good.

That said, I personally don't find it necessary to join the rat race. Instead, I'd suggest engineers just take time to thoroughly study just one book on algorithm designs. In fact, an introductory book, such as Kleinberg's Algorithm Design or Udi Manber's Introduction to Algorithms, will be good enough. It may not get you into Google, but it will likely get you into another damn good company. The best part of this approach is that passing interview is really just the byproduct of you trying to become a better engineer.