The process began with a technical phone interview, followed by time for me to ask questions. I found the interview very enjoyable and gained a positive impression of the company from the interviewer.

A few days later, I was invited for on-site interviews, which took place about two weeks after the initial call.

These subsequent interviews were less positive. The interviewers seemed less upbeat and more cynical or closed off.

After three interviews in the morning (technical, design, and technical), I was dismissed after lunch. Apparently, candidates who receive an offer have additional interviews in the afternoon.

How to find the intersection of two lists?

You have a list of integers. Figure out an algorithm that returns whether or not 3 elements in the list add up to 0.

Now, optimize it.

Now, do it for 4 elements. Optimize it.

Now, do it for k elements. Optimize it.