It's a simple question with radically different answers. I had people not knowing what it is, some says they find an existing library and few excitedly explain

It's a simple question with radically different answers. I had people not knowing what it is, some says they find an existing library and few excitedly explain on a whiteboard how they work, single vs double-linked etc. These days I would not reject an interviewee if they didn't know about linked lists, but depending on their answer it may be what makes their resume end up in the "2nd interview" pile instead of "maybe".