LeetCode 144. Binary Tree Preorder Traversal



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

For example:
Given binary tree {1,#,2,3},

return [1,2,3].

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


To return the preorder traversal of tree nodes values iteratively, we introduce a stack. With a stack, we can easily iterative nodes with preorder (root, left, right) sequence.

Video Tutorial

Java Solution

Leave a Reply

Your email address will not be published. Required fields are marked *