Today's Challenge

https://leetcode.com/problems/count-good-nodes-in-binary-tree/

Count Good Nodes in Binary Tree - LeetCode

3일 연속 DFS 문제 풀이

class Solution:
    def goodNodes(self, root: TreeNode) -> int:
        if not root:
            return 0
        
        def dfs(node, cur_max):
            if not node:
                return
            if node.val >= cur_max:
                count[0] += 1
                cur_max = node.val
            dfs(node.left, cur_max)
            dfs(node.right, cur_max)
        
        count = [0]
        dfs(root, root.val)
        
        return count[0]