I also interviewed at google, in the in-person all of the algos I got were very fair in my opinion, in that it took a little bit of thought to figure out what I needed to do, and then after that, most of the work was just turning that idea into an algorithm. It was all on the whiteboard but I thought it was fair. They were fine with little errors and we talked through them.
On the phone interview I was asked how to something I had no idea how to do. I have no idea how I passed the phone interview.
Seems like a mixed bag, the question as far as I know is completely up to the interviewer, which makes the interview very subjective when they don't use a normal question.
