Google Software Engineering Intern interview questions

had two phone interviews. Both interviews consist of coding for given problems. Only coding..not asked my research or interest area even though I am a phd candidate who mainly research on specific topic.

Applied online through their job portal and got contacted by a recruiter about 3 weeks later and was scheduled two technical phone interview. The first round went well but the 2nd one with a different interview was much more difficult. He asked me something about databases and I said I haven't learned that yet(i think it's reasonable considering I am only a freshmen at college) then he changed to another question about bit manipulation, which is also unfamiliar to me.