Given a n-ary 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.

For example, given a 3-ary tree:

 

 

We should return its max depth, which is 3.

 

Solution:

"""
# Definition for a Node.
class Node(object):
    def __init__(self, val, children):
        self.val = val
        self.children = children
"""
class Solution(object):
    # DFS
    def maxDepth(self, root):
        """
        :type root: Node
        :rtype: int
        """
        if not root:
            return 0
        curMax = 1
        for element in root.children:
            curMax = max(curMax, self.maxDepth(element)+1)
        return curMax

class Solution(object):
    # BFS
    def maxDepth(self, root):
        """
        :type root: Node
        :rtype: int
        """
        #层序遍历 用队列
        q, level = root and [root], 0
        while q:
            q, level = [child for node in q for child in node.children if child], level+1
        return level