Interviewed with Yahoo as a new college grad.

One phone coding interview, then invited to onsite for the final interview where I had four one-on-one coding/puzzle interviews.

The process took an extremely long time, and my HR contact was very unorganized.

The most difficult question asked was to prove the upper bound on the number of nodes in a balanced binary tree. To prove it, the interviewer was looking for an inductive proof (this question caught me extremely off guard; I hadn't done proofs in about three years). It was definitely one of the more difficult interviews I have had, but I was very unprepared.

My phone interviewer told me to expect an intense onsite coding interview where I would be expected to write an iOS application (my experience is in mobile applications, and I was interviewing for Yahoo Sports mobile). As a result, I spent a lot of time studying and practicing OOP and writing Objective-C code. Much to my surprise when I was invited onsite, my interview consisted simply of whiteboard coding questions. Most of the questions were binary tree and graph algorithm questions.

In retrospect, I could have done much better on this interview if I had not been misled by the previous engineer. Some of the questions included:

• Deep copy of a graph
• Dijkstra's algorithm
• Order level tree traversal
• Big integer addition

In short, do not rely on engineers or HR to help you; study on your own and focus on graphs and trees.

HR made it a terrible experience. The engineers were also very anti-social and seemed to only care if you got the question right, without regard for your approach. I also kept getting interrupted rudely while trying to write down code, which confused me a lot and made me perform even worse. There's no point in working for or with people like that; imagine the frustration!