In a family tree of pumpkin weights, every node holds a weight and a child is a grower if its weight is strictly larger than its parent's weight. Given the root, return how many growers the tree has. The root has no parent and is never a grower.
Examples
5
/ \
3 8
/ \ \
6 1 8
Input: root = build_tree([5, 3, 8, 6, 1, None, 8])
Output: 2
Explanation: 8 > 5 and 6 > 3. The leaf 8 equals its parent 8, so it does not count.
Input: root = build_tree([7])
Output: 0
Constraints
0 <= number of nodes <= 2000-10**4 <= node.val <= 10**4- Target complexity: O(n) time.
Goals
- Carry the parent's value through the traversal
- Compare each child with its own parent only
- Exclude the root, which has no parent