I had one phone interview, then met on-site with a small number of developers during a single day. All interviews were highly technical, focusing on algorithm design, improvement, and ways to parallelize computation.

One interviewer was discourteous and impolite. When I misinterpreted a request, he was quite rude in pointing out that my answer was of a wholly different format than he was expecting. We did not get along, and as a result, I did not fare terribly well. In every other interview, I believe I did very well or better.

I also got along well with every other interviewer. In my limited experience, the reports of rude or dispirited Google employees are quite exaggerated.

I strongly suspect that a single mediocre report is enough to scuttle an interview, regardless of the others. My advice:

• Be prepared for people you don't get along with (as with any interview!).
• Ask questions if there's even a hint of vagueness in your task.
• Have fun.

NDA; I don't want to comment.

In general, be prepared to divide and conquer in every way possible.

Also, dynamic programming would be a good subject of study.