I met a manager at a university job fair. After completing a skills test, he grilled me on my answers for about an hour.

The first phone interview was with the same manager. It was supposed to be 45 minutes but was very difficult and took an hour and a half, with one question alone taking about half an hour.

I ended up doing four interviews in total: one at the job fair and then three phone interviews over four weeks. All took at least an hour, so when they say to schedule 45 minutes, give yourself some additional time.

The process with NVIDIA is very frustrating. I think I was only supposed to have three rounds, but their intra-company communication isn't very good. It then took over three weeks after the last interview for them to decline me, leaving me wondering if the accidental fourth interview cost me the job.

They are notoriously rigorous in their selection process, and you will feel it in the interview. If you get a question right, they will press you until you screw up to test your limits. I think the interviews are best described as demoralizing, as they invariably will find your weaknesses.

All things considered, I was very impressed and came away knowing that the level of talent at NVIDIA must be consistently high. Getting an offer would provide a great sense of accomplishment. Don't be alarmed if they don't contact you quickly; they're just (extremely!) disorganized.

Write a function to swap n bits of a variable from position x and position y.

What's wrong with [sample code]? Sometimes it's just a few lines; sometimes it's an entire function.