I'm a micro-optimization and numerics guy by trade (mostly I write math libraries); they are almost completely irrelevant to my area of work.
Priority queues should be covered in a competent introductory data structures course. Bloom filters are marginally more obscure, but I still expect a good candidate to have come across them at some point. They're so widely used that it's pretty hard to avoid learning about them if you've done any significant amount of work or just spend time reading HN (they come up in someone's blog every month or so).
Note that I said "would hesitate to", not "wouldn't hire". If someone were otherwise a strong candidate, but happened to not be familiar with these, I would almost surely still hire them.
I should clarify that a typical candidate for a junior position on my team is either coming from graduate school or has 3-5 years experience in industry. I have correspondingly higher expectations for their background knowledge.
Bloom filters are marginally more obscure, but I still expect a good candidate to have come across them at some point.
Possibly in your area the candidates you get may have come across them, but then they wouldn't be junior engineers, by definition. If you're advertising for "strong algorithms" candidates then sure, but I bet half the people reading this have never used or come across any probabilistic data structure!
> then they wouldn't be junior engineers, by definition
I don't think so. My impression is that junior/senior is defined by years of experience more than technical skills. Having been out of university for one year now, I know I sure as hell won't get a job as a "senior engineer" anywhere, even if I could easily implement both these structures.
Priority queues should be covered in a competent introductory data structures course. Bloom filters are marginally more obscure, but I still expect a good candidate to have come across them at some point. They're so widely used that it's pretty hard to avoid learning about them if you've done any significant amount of work or just spend time reading HN (they come up in someone's blog every month or so).
Note that I said "would hesitate to", not "wouldn't hire". If someone were otherwise a strong candidate, but happened to not be familiar with these, I would almost surely still hire them.
I should clarify that a typical candidate for a junior position on my team is either coming from graduate school or has 3-5 years experience in industry. I have correspondingly higher expectations for their background knowledge.