Thomson Reuters Software Engineer interview questions

First round is a very basic array manipulation algorithm. The terrible part is the second round whiteboard coding where the interviewer started late for about 20 min (technical issue from previous) and ended it 10 min earlier! He did not specify his question clearly at all, and after my first quick check with him before coding, he did not stop me from coding the wrong thing then told me the "actual" question???I've never been to an onsite interview messy like this. It's only till the latter half of the interview when he just changed the problem description, then I understood what he was actually going to test me about. When I tried to re-organized my idea, it was way too late. There's NO positive or meaningful discussions during this interview. I'm really angry about how much hard work I put into interview preparation and then just ended up like that!