Count Good Nodes in Binary Tree

Given a binary tree root, a node X in the tree is named good if in the path from the root to X there are no nodes with a value greater than X.val.

Return the number of good nodes in the binary tree.

---

Example 1

        3
       / \
      1   4
     /   / \
    3   1   5

Input: root = [3, 1, 4, 3, null, 1, 5]
Output: 4
Explanation: Nodes 3 (root), 3 (left-left), 4, and 5 are good. Node 1 (left child of root) is not good because 3 > 1 on the path. Node 1 (left child of 4) is not good because 4 > 1 on the path.

Example 2

    3
   /
  3
   \
    4
     \
      2

Input: root = [3, 3, null, null, 4, null, null, null, 2]
Output: 3
Explanation: Nodes 3 (root), 3, and 4 are good. Node 2 is not good because 4 > 2 on the path.

---

Constraints

• The number of nodes in the binary tree is in the range [1, 10^5].
• Each node's value is between -10^4 and 10^4.