g0101_0200.s0145_binary_tree_postorder_traversal.readme.md Maven / Gradle / Ivy
145\. Binary Tree Postorder Traversal
Easy
Given the `root` of a binary tree, return _the postorder traversal of its nodes' values_.
**Example 1:**

**Input:** root = \[1,null,2,3\]
**Output:** \[3,2,1\]
**Example 2:**
**Input:** root = \[\]
**Output:** \[\]
**Example 3:**
**Input:** root = \[1\]
**Output:** \[1\]
**Example 4:**

**Input:** root = \[1,2\]
**Output:** \[2,1\]
**Example 5:**

**Input:** root = \[1,null,2\]
**Output:** \[2,1\]
**Constraints:**
* The number of the 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? © 2015 - 2025 Weber Informatics LLC | Privacy Policy