sy-lingting/leetcode — pull request #1 by HisenWu (2014-02-28 08:44:56+00:00)
Title: Binary Tree Preorder Traversal

Given a binary tree, return the preorder traversal of its nodes' values.

For example:
Given binary tree {1,#,2,3},
1
\
2
/
3
return [1,2,3].

Note: Recursive solution is trivial, could you do it iteratively?