public class Solution
extends Object
637 - Average of Levels in Binary Tree\.
Easy
Given the `root` of a binary tree, return _the average value of the nodes on each level in the form of an array_. Answers within 10-5 of the actual answer will be accepted.
**Example 1:**
**Input:** root = [3,9,20,null,null,15,7]
**Output:** [3.00000,14.50000,11.00000] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and on level 2 is 11. Hence return [3, 14.5, 11].
**Example 2:**
**Input:** root = [3,9,20,15,7]
**Output:** [3.00000,14.50000,11.00000]
**Constraints:**
* The number of nodes in the tree is in the range [1, 104].
* -231 <= Node.val <= 231 - 1