[LeetCode][Python] 104. Maximum Depth of Binary Tree

- 문제 링크: https://leetcode.com/problems/maximum-depth-of-binary-tree/

- 난이도: Easy

 

binary tree의 max depth를 구하는 문제

class Solution:
    def maxDepth(self, root: Optional[TreeNode]) -> int:
        if not root:
            return 0

        def bt(curr_depth: int, node: TreeNode) -> int:
            # leaf
            if not node.left and not node.right:
                return curr_depth
            
            max_depth = 0
            if node.left:
                max_depth = max(max_depth, bt(curr_depth+1, node.left))
            if node.right:
                max_depth = max(max_depth, bt(curr_depth+1, node.right))
            return max_depth

        return bt(1, root)