Well it kind of depends, doesn't it? Linked Lists are a good introduction to the types of structures you'll use in any sort of graph-related problems. If the wo

Well it kind of depends, doesn't it? Linked Lists are a good introduction to the types of structures you'll use in any sort of graph-related problems. If the work you're interviewing for is going to involve a lot of manipulations of node trees and graphs and lists, then you'd want someone who either knows that stuff or seems capable of understanding it. Certainly not knowing it doesn't disqualify you from being "a real programmer" or whatever. If you never use one, then there's no shame in not knowing it. (Though it's good to learn things you haven't used because maybe there are better ways to do what you're doing.) But it's not a flaw of the interviewer to ask questions related to the work the candidate will be expected to do, either.