Salesforce interview question

Describe/code a Binary Tree implementation, code function to find a node in a binary tree, a binary search tree, code a function to add a node into a binary search tree, describe a technical project you've completed, there was a debugging question where they described a web application to me and asked me what I would do in certain scenarios where some sort of behavior was not working correctly. (3rd party APIs, callbacks, timeouts on requests, thread usage/exhaustion etc.)