Google Software Development Engineer interview questions

The process was very smooth but I felt the interview was a bit unfair. The question was somewhat new and I could get no where near to cracking it in 15-20 min. It was about some left closed right intervals something (don't remember the exact details) but knew it was some interval tree question. I have seen people get much easier questions in their first round interview. I guess these interviews tend to get random and I was just plain unlucky to have got a very difficult (and unforgiving) interviewer right at the very beginning.