Tree BFS
LC #102Medium
Binary Tree Level Order Traversal
Tree BFS
AmazonGoogleMetaMicrosoftBloombergProblem
Return the level-order (BFS) traversal of a binary tree as a list of lists.
treebfsqueue
Constraints
- ›0 ≤ n ≤ 2000
- ›-1000 ≤ Node.val ≤ 1000
Example
Input
root = [3, 9, 20, null, null, 15, 7]Output
[[3], [9, 20], [15, 7]]Why
Level 0: [3], Level 1: [9,20], Level 2: [15,7]