> Whether it's in Google's interest to select for that of course is debatable.
I'd argue it does not. Computational geometry is a niche. It's not even a niche that's particularly relevant to most of Google's development operations.
In modern software development, knowing the detail of specific algorithms off the top of your head and being able to implement them unaided is, at best, a parlor trick. I doubt very much that it even correlates to one's effectiveness as a developer. Even for development tasks which involve algorithmic work -- which many don't! -- knowing that various algorithms exist, and what they're used for, is much more valuable than having memorized the details of how those algorithms are implemented.
The idea is that you might need to invent a new algorithm where a technique from an existing algorithm is used in a modified way or in a new setting, and then knowing the actual technique can be essential to find an inspiration.
E.g. if you know that convex hulls can be computed by sorting by angle and sweeping, then you might come up with the idea of sorting by angle and sweeping in problems that are unrelated to convex hulls (e.g. determining what is visible from a given point in an environment with obstacles).
In general, if you know a lot of those techniques and heuristics, you will be much more effective at problem solving in domains where these techniques apply.
It is relatively rare for this to be a big factor in routine software development, so that's probably something one should filter for only if interviewing for roles where you might need to design novel algorithms (which Google probably has more than the average company).
I'd argue it does not. Computational geometry is a niche. It's not even a niche that's particularly relevant to most of Google's development operations.
In modern software development, knowing the detail of specific algorithms off the top of your head and being able to implement them unaided is, at best, a parlor trick. I doubt very much that it even correlates to one's effectiveness as a developer. Even for development tasks which involve algorithmic work -- which many don't! -- knowing that various algorithms exist, and what they're used for, is much more valuable than having memorized the details of how those algorithms are implemented.