For BST http://www.leetcode.com/2010/09/saving-binary-search-tree-to-file.html

I know that some people didn't get to the de-serialization code...so it might be a bit long. The question itself is pretty basic so the objective should be to provide a clear explanation and code. Interviewer seemed happy that I didn't jump straight to the solution, but instead inquired about any system restrictions, requirements etc.