28 lines
596 B
Markdown
28 lines
596 B
Markdown
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Given the `root` of a binary tree, return _the level order traversal of its nodes' values_. (i.e., from left to right, level by level).
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**Example 1:**
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Input: root = [3,9,20,null,null,15,7]
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Output: [[3],[9,20],[15,7]]
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**Example 2:**
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Input: root = [1]
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Output: [[1]]
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**Example 3:**
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Input: root = []
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Output: []
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**Constraints:**
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* The number of nodes in the tree is in the range `[0, 2000]`.
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* `-1000 <= Node.val <= 1000`
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https://leetcode.com/problems/binary-tree-level-order-traversal/
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