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maximum depth of binary tree

admin 11月 13, 2020 0

Maximum Depth of Binary Tree

Given a binary tree, find its maximum depth.
The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
Note: A leaf is a node with no children.
Example:
Given binary tree [3,9,20,null,null,15,7],

return its depth = 3.

translation

给定一个二叉树，找出其最大深度。
二叉树的深度为根节点到最远叶子节点的最长路径上的节点数。
说明: 叶子节点是指没有子节点的节点。

solution

Definition for a binary tree node.
class (object):
    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None
class Solution(object):
    def maxDepth(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        if root is None:
            return 0
        else:
            ldepth = 1+ self.maxDepth(root.left)
            rdepth = 1+ self.maxDepth(root.right)
            return max(ldepth, rdepth)