README_CN.md

589. N叉树的前序遍历

给定一个 N 叉树，返回其节点值的前序遍历。

例如，给定一个 3叉树:

返回其前序遍历: [1,3,5,6,2,4]。

说明: 递归法很简单，你可以使用迭代法完成此题吗?

题解 (Python)

1. 递归

"""
# 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]:
        if not root:
            return []
        vals = [root.val]
        for child in root.children:
            vals.extend(self.preorder(child))
        return vals

2. 迭代

"""
# 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]:
        vals = []
        nodes = [root]
        while nodes:
            cur = nodes.pop()
            if cur:
                vals.append(cur.val)
                for n in cur.children[::-1]:
                    nodes.append(n)
        return vals