I interviewed with 4 different groups which was helpful for getting an overview of different roles in the company. Initially, I applied for one position, but several HR recruiters got back to me quickly, which was awesome compared to other companies that seem not to care. Mostly questions about C++ and lots of questions related to graph algorithms. There is a spectrum of groups from legacy products/code that are being optimized to new products. Some of the groups have harder interviews than others, but preparing for standard algo questions should get you there. Also, some groups have an emphasis on parallelism and distributed systems/scheduling, which would also be good to brush up on.