Google has interviewed tens of thousands of candidates in this manner. Other companies have interviewed even more, using roughly the same process. With all the preparation this girl put into her interview, I don't see how she possibly could have been surprised by those types of questions. The first piece of advice anyone will give you is that the final answer is not nearly as important as talking through the process you would use to solve the problem. Obviously she never even read that first piece of advice, because she blurted out a wild guess to the very first question. Don't let this happen to you!

Google's interview process isn't a nightmare. It's entirely typical. If you plan on interviewing for any job, you should spend a lot of time studying the interview process and how to excel in it. If you're interviewing for programming jobs, this course is an invaluable resource: http://courses.csail.mit.edu/iap/interview/

Read all the handouts 5 times, and you won't be caught off guard like this girl was.