3997. Count Dominant Nodes in a Binary Tree

Input: root = [5,3,8,2,4,7,1]

Output: 5

Explanation:

• The leaf nodes with values 2, 4, 7, and 1 are dominant.
• The node with value 8 is dominant because its value is the maximum value in its subtree [8, 7, 1].
• Thus, the answer is 5.

Input: root = [1,2,3,1,2]

Output: 4

Explanation:

• The leaf nodes with values 1, 2, and 3 are dominant.
• The node with value 2 whose subtree is [2, 1, 2] is dominant because its value is the maximum value in its subtree.
• Thus, the answer is 4.