One phone interview was conducted using Google Docs. Fifteen minutes were spent explaining the problem. The problem was not difficult, but the interviewer felt the time complexity of my solution was not good enough. For this problem, it was easier to code in C++, as it could be solved by updating elements in a heap. I did not get to ask any questions at the end.

A problem can be solved by using a heap. You must know how to extract the min/max from the heap, and how to delete or update an element in the heap.