Really two ways to traverse: Depth First Search Breath First Search DFS - can be implemented w/stack (favors going deep off right nodes), preorder (going deep off left nodes and processing parent nodes before children), postorder (going deep off left node and processing children nodes first). BFS - from left to right, level by level, usually implemented with a queue. Which to use is very nuanced. This is a terrible interview question since it's not the algorithm that's important, since the algorithms are already written, but it's the nuance of applying the right search type.