Average of Levels in Binary Tree

Average of Levels in Binary Tree

Given the root of a non-empty binary tree, return the average value of the nodes on each level in the form of an array.

Examples

Example 1:

Input: root = [3, 9, 20, null, null, 15, 7]
Output: [3.0, 14.5, 11.0]

      3
     / \
    9  20
       / \
      15   7

Example 2:

Input: root = [3, 9, 20, 15, 7]
Output: [3.0, 14.5, 11.0]

Constraints

• The number of nodes in the tree is in the range [1, 10^4].
• -2^31 <= Node.val <= 2^31 - 1

Expected Complexity

• Time: O(n)
• Space: O(n)