Count Good Nodes in Binary Tree

Medium

A node is good if no node on the path from the root to it has a greater value. Given the root, return the number of good nodes.

Example 1

Input:  root = [3,1,4,3,null,1,5]
Output: 4

Example 2

Input:  root = [3,3,null,4,2]
Output: 3

Constraints

• 1 <= number of nodes <= 10^5
• -10^4 <= Node.val <= 10^4