Skype interview questions

First I got the phone interview by a recruiter and I was asked basic questions about my experience and plans for my career. Also I was asked simple questions from OOP like what are the virtual functions and what are deadlocks. She was friendly and overall I am happy with it. The next on site interview stage was booked in approximately 2 weeks with the Desktop Team leader. He asked some more technical questions about threads, synchronization, race conditions and locking. It was followed by the theoretical algorithm questions like: sorting, heaps, trees, balanced red-black trees and running times. For the last test he asked me to solve a FizzBuzz problem in a notepad on a large screen, which was done easily. He explained to me the projects his team was working on and the project planning that went into it. Overall I had a good impression so far. Next was more technical interview, again on site, for which I prepared by remembering all the advanced algorithm stuff, but as it turned out it was not needed. Problems were really easy actually. But there was a problem with the interviewer and the atmosphere during the interview. (see problems below). First time was quite short considering that you re writing code in a notepad, on a large screen in front of the interviewer. Strictly half an hour for each problem. Interviewer kept the pressure of reminding you about the time limit. I solved the first problem quite easily but the problem was that the interviewer was not convinced. I tried to prove my solution, since it was not possible to run it, but instead I was reminded was time was up and there is nothing to do about it. I checked my solution at home and it worked. The next problem was a bit harder but still easy overall. I solved it by a recursion and hash table because the code was smaller this way and time was my main concern. At this moment interviewer was not paying any attention and was just playing with his smartphone. This was very unpleasant also. Interviewer said the solution was correct but still he was not happy about it but since there was no time left I had no chance to improve it. I made the running time analysis for the second problem.