- Difficulty: Easy
- Tags: LeetCode, Easy, Stack, Tree, Depth-First Search, Binary Tree, leetcode-94, O(n), O(1), Medium, Morris Traversal, LintCode, EPI
Problem
Given the root of a binary tree, return the inorder traversal of its nodes' values.
Example 1:
Input: root = [1,null,2,3] Output: [1,3,2]
Example 2:
Input: root = [] Output: []
Example 3:
Input: root = [1] Output: [1]
Constraints:
- The number of nodes in the tree is in the range
[0, 100]. -100 <= Node.val <= 100
Follow up: Recursive solution is trivial, could you do it iteratively?