I applied at Snapchat and interviewed via Google Hangouts. I answered every question correctly, except for the coding portion. The outcome of that portion was to remove two return statements and move a comparison operation in front of the base case.

My interviewer did not seem to understand very basic CS concepts. After he admitted he didn't remember the merit of using a Linked List or when to use one, I explained that Linked Lists are faster for insertions and removals.

I went above and beyond in explaining the questions and how they related to concepts I knew, outside of what was asked. Because of this, I was told I gave a sufficient answer during the coding portion, though the interviewer suggested it might be good to debug the solution while talking. I answered their questions very well, explained my thought process, and followed the interview process closely. Therefore, I didn't see much room for improvement, yet I was still rejected because I was not 'a perfect match in the qualities sought in the iOS Engineering position.' I do not understand this decision at all, based on my performance.

Write a function to calculate the height of a binary tree.

What are the merits of using an ArrayList versus a LinkedList?

How would you implement Merge Sort and Quick Sort? What are their time complexities?