LeetCode104 二叉树的最大深度（DFS）

LeetCode104 二叉树的最大深度（DFS）

DFS递归

# Definition for a binary tree node.
class TreeNode:
    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None

class Solution:
    def maxDepth(self, root: TreeNode) -> int:
        if not root: return 0
        ans = 0
        ans = self.dfs(root)
        return ans

    def dfs(self, bt: TreeNode):
        if not bt: return 0
        ld = self.dfs(bt.left)
        rd = self.dfs(bt.right)
        return max(ld,rd) + 1