Meta Software Engineer Internship interview questions

Two standard phone interviews (similar to how Google, Amazon or pretty much any other company does their phone screens). Got an email later with their offer. It was really fast, HR was very pleasant to work with compared to other experiences.

On-campus interview. The interviewer was friendly and introduced himself. A few minutes of resume discussion and then the technical question on the whiteboard. I worked the problem out in pseudocode and then in code, making sure to think out loud. A few days later I was invited to the on-site, which hasn't yet happened.