#102
Binary Tree Level Order Traversal
medium · verified · 72.2% accepted · 16,967 likes · top 81%
tree · breadth-first search · binary tree
Description
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).
Example 1:
Input: root = [3,9,20,null,null,15,7]
Output: [[3],[9,20],[15,7]]
Example 2:
Input: root = [1]
Output: [[1]]
Example 3:
Input: root = []
Output: []
Solution