Meta Software Engineer Internship interview questions

I submitted my resume online via their job app. I was contacted by a recruiter about two weeks after that. I had one ~45-60 minute phone interview with an engineer where we walked through a BST problem. He asked several successive questions about optimisation and making the algorithm more memory/space efficient. Then, I interviewed with a member of the personalised video team at the Menlo Park location during one of their UDay events. The interview was also about an hour and I walked through two questions on a whiteboard. Very friendly employees, cool campus, but not much feedback from the interview process overall :(