# LeetCode Algorithm Challenge: Binary Tree Inorder Traversal

# Question

Given the `root`

of 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]

**Example 4:**

**Input:** root = [1,2]

**Output:** [2,1]