Python3解leetcode N-ary Tree Level Order Traversal

发布时间：2020-12-20 12:46:27 所属栏目：Python 来源：网络整理

导读：问题描述： Given an n-ary tree,return the level order traversal of its nodes‘ values. (ie,from left to right,level by level). For example,given a? 3-ary ?tree: ? ? We should return its level order traversal: [ [1],[3,2,4],[5,6]] ? Note: T

问题描述：

Given an n-ary tree,return the level order traversal of its nodes‘ values. (ie,from left to right,level by level).

For example,given a?3-ary?tree:

We should return its level order traversal:

[
     [1],[3,2,4],[5,6]
]

Note:

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

思路：此题是在leetcode上见到的第一个BFS的题目，因而记录。同时注意该句代码应用方式?Node,level = queue.pop()

代码：

 1 """
 2 # Definition for a Node.
 3 class Node:
 4     def __init__(self,val,children):
 5         self.val = val
 6         self.children = children
 7 """
 8 class Solution:
 9     def levelOrder(self,root: ‘Node‘) -> List[List[int]]:
10         if not root:
11             return []
12         
13         result,queue = [],[(root,1)]
14         while queue:
15             Node,level = queue.pop()
16             if level - len(result) >= 1:
17                 result.append([])
18             result[level - 1].append(Node.val)
19             
20             for child in Node.children:
21                 queue.insert(0,(child,level+ 1))
22         return result

（编辑：李大同）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!