Standard algorithms question based on how to locate two elements in an array that have a certain sum. Can you do it in linear time? You'll also be asked to share your screen with your interviewer during the phone interview, and implement a certain algorithm. You should be prepared to talk about your implementation while you're writing it, and explain possible issues with your code (assumptions you made, places for error/where your code could break, etc.). I highly recommend reviewing algorithms online before interviewing.