数据结构：树🌲

时间复杂度：O(n)

空间复杂度：O(n)

代码实现：

class Solution:def goodNodes(self, root: TreeNode) -> int:counter = [0]def dfs(root, val):if not root: returnnext_val = valif root.val >= val:counter[0] += 1next_val = root.valdfs(root.left, next_val)dfs(root.right, next_val)dfs(root, -10e9)return counter[0]