I had a terrible experience with Picovoice recently. I interviewed for their Deep Learning role, and I solved their pre-screen perfectly and spent 3 days on it. The CEO even got back to me and asked me to improve further tools in the repository, which I added, and I had even re-programmed several unit tests and architected some of the codes into a better MVC-esque format. I was called to the virtual on-site. The CEO (Mr. Alireza) was very rude and called me incompetent (you're terrible at coding right now, and I'll never extend an offer to someone like you, and you need to study a lot) after I took some time to figure out an LC Medium (30 minutes?). I found that VERY unprofessional. For context, I don't think I'm terrible, I'm sitting on offers that pay me well over 2x of his pay with 2 YOE, from decently sized companies. He told all the other engineers in his team to disconnect the call and cancel further rounds immediately and didn't bother to check my resume or any other technical skills or ask me about myself. I'd expect the interviewer to at least conduct the interview properly instead of cutting me off in the middle. Mr. Alireza pays only 60k to 90k for Deep Learning fresher roles (according to his old Angel List post), and I'd say if he pays that + is rude to employees, it's abysmal. He very clearly does *not* value the time you take out from your work to work on his assignment that can take up to 20-40 hours. Find better roles. Also, his employee strength reduced from 10 to 7 in the past year (as of writing this answer). According to public information available on LinkedIn: 1-2 of the senior engineers/founders left him to join other companies or start their own ventures too. He's clearly horrible at managing his employees, and unless he learns a bit, he's crashing very soon. He does not value your seniority or experience building software too.

Solve a list of assignments, including implementation of algorithms and models from research papers from scratch using basic Python libraries (numpy), then technical interview that has three parts, the first one is the hardest, you are told to extend the theory of an algorithm to a real time application and figure out a way to make it work