The interview process began with a phone/computer interview. I was on the phone with a software engineer, and we were sharing an online whiteboard to look at code. I was given a short program in Java (equivalent programs in other languages were available) and asked to identify what it did. I was then asked to optimize the code to make it faster and to analyze its Big-O complexity.

The second round of interviews was on-site and face-to-face. I was asked to solve problems on the whiteboard.

General advice:

You really have to know your fundamental data structures and algorithms inside out. Trees, graphs, linked lists. Don't forget Big-O.

You have a simple search consisting of search terms that are OR'ed together. For example: "Cats" OR "Dogs". You have a set of documents that possibly contain those terms, and you have the positions of those terms in each document. How would you search for "Cats" AND "Dogs"?