What is a binary tree and why would I ever want to reverse it

from blog Frederick's delirious rantings, | ↗ original
You have probably already heard the horror stories of code interviews where they ask you to reverse a binary tree on a whiteboard. (if not check this blog post that I profoundly disagree with) Well, a few days ago I was in that exact situation. And I had no idea what the interviewer was talking about. So what are these binary trees and why is it...