geeksambhu

'''
Interview hack: Memorize preorder/inorder/postorder tree ITERATORS (no recursion) and their reverses.
It simplifies a disproportionate number of questions to simple for loops (see below).

I consider the implementations below the simplest way to memorize the iterative tree traversal algorithms,
because they are so similar to each other, and to their respective recursive versions.

Notes:
- We only visit a node after we have expanded its children (i.e. added them to the stack) in the desired order.
- `x is curr` does the expanded flagging for us, because we always expand the current node.

geeksambhu

Programming Achievements: How to Level Up as a Developer

This gist is part of a blog post. Check it out at:

http://jasonrudolph.com/blog/2011/08/09/programming-achievements-how-to-level-up-as-a-developer