Level order traversal of a binary tree
Coding problemEasy-MediumAsked in: Adobe, Amazon, Flipkart, Microsoft, Qualcomm, Samsung
Given the root of a binary tree, return its values level by level: one list per level, from the top level down, with the values of each level from left to right.
Trees are written in level order, with null for a missing child. An empty tree gives an empty list.
Examples
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: []
Constraints
- The tree has between 0 and 100,000 nodes
- Each value is a 32-bit integer
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