zoom interview, some ML questions about tree algorithm complexity, regularization, and bias-variance tradeoff. one question required deriving the conditional gaussian formula through an optimization problem or any other way, which might not be so trivial if you've never done it.

The interview took a long time. 7 rounds of technical. 4 reference calls scheduled. Most people I talked to were nice. The same junior interviewer with bad attitude during my process was put to call one of my references and the reference told me that he was disrespectful and act very uninterested. Apparently they ask: does he respond to pings in after hours promptly and things like that. They ended up saying that reference didn’t provide enough info and asked for more references to call! Interviewing is a huge investment. And I would say like any other place you might get unlucky to get matched with some biased / unhappy folks. I would not recommend doing an interview as the opportunity cost is too high and you need to ask for many references time as well. Wasting your time is one thing but wasting other people’s time is a horrible addition.

First technical, 4 interviews on full day, ref checks - they were prompt, eager to talk but threw very junior guys to interview - at some point i thought these guys have been hired just to interview and not really to do research as they were too bookish in their knowledge.