# 559. Maximum Depth of N-ary Tree N 叉树的最大深度

@TOC

## # 题目描述

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.

Note:

1. The depth of the tree is at most 1000.
2. The total number of nodes is at most 5000.

N叉树的高度。

## # 解题方法

### # DFS

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

### # BFS

``````"""
# Definition for a Node.
class Node(object):
def __init__(self, val, children):
self.val = val
self.children = children
"""
class Solution(object):
def maxDepth(self, root):
"""
:type root: Node
:rtype: int
"""
if not root: return 0
depth = 0
que = collections.deque()
que.append(root)
while que:
size = len(que)
for i in range(size):
node = que.popleft()
for child in node.children:
que.append(child)
depth += 1
return depth
``````

## # 日期

2018 年 7 月 12 日 —— 天阴阴地潮潮，已经连着两天这样了 2018 年 11 月 6 日 —— 腰酸背痛要废了