First, there was a technical phone interview with a fairly straightforward programming problem using Google Docs to write on. Then, I heard back to schedule the onsite portion.

Flights and hotel were paid for, and they were rather flexible to work with my schedule.

The onsite interview included four technical questions, with lunch after the first two. All the questions were fairly difficult; they skipped right past the easy ones and only talked briefly about my resume and experience.

Definitely know Big O notation and be able to calculate the time complexity for any code you write. A lot of problems involved graphs or matrices, but also included other data structures.

They gave me a full list of what I should know beforehand, and much of it was covered.

What is the time complexity of your implementation?

What is the space complexity?

Can it be done faster?

Can it be done with less space?

Write a new implementation doing both.