LeetCode 589 N-ary Tree Preorder Traversal 解题报告

题目要求

Given an n-ary tree, return the preorder traversal of its nodes' values.

题目分析及思路

题目给出一棵N叉树，要求返回结点值的前序遍历。可以使用递归的方法做。因为是前序遍历，所以最开始就加入根结点的值。

python代码

"""

# Definition for a Node.

class Node:

def __init__(self, val, children):

self.val = val

self.children = children

"""

class Solution:

def preorder(self, root: 'Node') -> 'List[int]':

order = []

if not root:

return order

order.append(root.val)

for child in root.children:

order.extend(self.preorder(child))

return order