Welcome to your interview.
The question is on your right: Optimized Array Intersection. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
Given two arrays, write an optimized algorithm to find their intersection. What is the time complexity of your approach?