The response from HR was fast; she helped me arrange everything about the interview. However, one of the interviewers was not very friendly. He just pasted questions on a Google Doc and remained silent the whole process. The second interviewer was more friendly. He asked questions but more like discussed them with me and asked questions by speaking. When I was stuck on something, he also gave me some hints to solve that question.

Find duplicate elements from an array.

How about in a very large file that can't be loaded into memory?