leetcode 559. Maximum Depth of N-ary Tree

"""
# Definition for a Node.
class Node:
    def __init__(self, val, children):
        self.val = val
        self.children = children
"""
class Solution:
    def maxDepth(self, root: 'Node') -> int:
        
        def getMaxdeep(root, deep, max):
            #if len(root.children) == None:
            if len(root.children) == 0:
                print(deep)
                if deep > max:
                    max = deep
                    return max
           
            for i in range(len(root.children)):
                max = getMaxdeep(root.children[i], deep+1, max)
                # deep-=1 ,每次循环deep都会自动回溯，因此不用再此处回溯
            return max
             
        max = 0
        if not root:
            return 0
        return getMaxdeep(root, 1, max)