Pre-order traversal is a useful technique when you want to copy or clone a binary tree, or when you want to print the tree in a hierarchical structure. To implement pre-order traversal in Python ...

Given a binary tree, return the preorder traversal of its nodes' values. Example: Input: [1,null,2,3] 1 \ 2 / 3 Output: [1,2,3] Follow up: Recursive solution is trivial, could you do it iteratively ...

Given an array of integers preorder, which represents the preorder traversal of a BST (i.e., binary search tree), construct the tree and return its root.

Is there any way to implement a nonrecursive preorder traversal of a binary tree without using a stack? In a standalone function?the recursive preorder ...