559.N叉树的最大深度

https://leetcode-cn.com/problems/maximum-depth-of-n-ary-tree/

一、层序

"""
# Definition for a Node.
class Node:
    def __init__(self, val=None, children=None):
        self.val = val
        self.children = children
"""
import queue
class Solution:
    def maxDepth(self, root: 'Node') -> int:
        depth =0
        if not root:
            return 0
        q = queue.Queue()
        q.put(root)
        while not q.empty():
            depth += 1
            for _ in range(q.qsize()):
                node = q.get()
                for c in node.children:
                    if c:
                        q.put(c)
        return depth