A recruiter contacted from LinkedIn. Initial phone talk with recruiter then phone interview scheduled.
Instead of the actual person that is mentioned in coordinator's email, a different person called me. He asked several deep learning questions, and some debatable classical machine learning questions. I gave the right answers. The questions were cherry-picked and were not ideal for assessing theoretical knowledge. I guess the source of questions were topics that interviewer's own study schedule. The sentiment of interviewer's reactions that I received was not positive, I guess he did not like to receive the right answers.
Then he asked a programming question. It was a tricky tree question that I did not see before. I solve it. However, it was not working on the specific condition that he asked for. More specifically, it was working well when the tree is a complete tree, but failing when there were missing nodes.
Overall, I actually like the questions. However, the attitude of the interviewer was not nice and friendly. I believe he did not want me to pass the interview. I find him very unfriendly.
Unfortunately, this type of situation occurs in interviews, but I suggest Bloomberg select more suitable people for the interviews. Prospective candidates are investing time and taking time off from their work. The goal of the phone interview is assessing technical skills and theoretical knowledge in short amount of time, not debating or competing with an interviewer. A responsible interviewer should understand these aspects.