You did emphasize it was the best result, so it's hard to argue that you selected for it.

Back in 2015 Peter Norvig discussed an analysis at Google that suggested doing well at coding contests was a negative indicator of job performance: https://youtu.be/DdmyUZCl75s

Presumably they do well at these sorts of questions, but that doesn't imply the same actual effectiveness.

Perhaps there is a sort of selection bias going on, where the people who work at Google have been chosen because they are good at leetcode type problems and think they are important, and so they tend to solve problems by implementing their own tries and similar data structures, rather than by using robust canned implementations.

What algorithms and data-structures do you commonly use when shutting down useful services?

I think both things can be true. These are valuable skills in some situations/jobs and you're selecting for students with these concepts still fresh in their minds and/or people who enjoy algorithm competitions.

And that's fine! A specialized subset of engineers. Maybe that subset is exactly what you need.

I wonder how the stress of the interview process selects out people who understand O-notation and to whom a Trie would make sense if explained to them, vs people who have these concepts fresh in their minds and/or can handle themselves in stressful interview situations.

The author, everyone.

Would you care to extend your reply, and tell us how you use them? Just like you expect a good candidate to do ;)