Meta Intern Software Engineer interview questions

I emailed the recruiter and requested an interview. My first round interview was on the phone a week or so later. I heard back 3 days later.

Met at campus career fair Submitted resume Invited to first round. A lot of chatting, then tech questions. Invited to second round at HQ. Tech interview in the morning, then lunch, and A LOT more chatting, and getting to know Facebook. Questions. Round 1. 1. Function to check if 2 words are anagrams 2. Function to check if any 3 numbers sum to x. Round 2. You are given 2 streams of data, representing very sparse vectors you are guaranteed that the 2 incoming streams are of same size give a data structure which is optimized for producing the dot product of those sparse vectors analyze your runtime/space complexity, b) what if you are now told that v1, is much more sparse than v2 give another (or the same) data structure optimized for the dot product of any such 2 vectors (where 1 is more sparse than the other) analyze your runtime/space complexity,