I applied through a recruiter, and the process took two weeks.

I feel they just wanted to collect new ideas about how to solve their technical problems, without actually hiring anyone. The HR approached me; I didn't apply online. After meeting with the hiring manager, I was invited for an onsite interview very quickly. In the onsite interview, they literally asked me to solve the specific problems they were facing. They opened a notebook showing their actual problem and asked me for all possible ideas I could think of to solve that problem.

The one to two other technical interviews also went pretty much the same way, asking for all solutions I could think of, theoretically. In my opinion, these rounds went perfectly as I was able to literally answer all questions, even helping create a ML model on their real data with acceptable accuracy.

There was a coding challenge at the end, which was terrible. I mean the coding question was reasonable, but the interviewer was not. Any time I asked a question or made a comment that seemed wrong, the interviewer would quickly take notes on her computer. This was frustrating as she made it very obvious that she was taking notes on my mistakes.

After a few days, I received a call from the HR, and as I expected, he said they didn't move forward. He said they would like to stay in touch for future roles, but honestly, I don't want to get involved with them anymore.

What solutions can you propose to validate the ultrasound signals automatically? How do you implement them in code?