590. N-ary Tree Postorder Traversal

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

For example, given a 3-ary tree:

Return its postorder traversal as: [5,6,3,2,4,1].

Note:

Recursive solution is trivial, could you do it iteratively?

# Definition for a Node.
class Node(object):
    def __init__(self, val, children):
        self.val = val
        self.children = children



class Solution(object):
    def postorder(self, root):
        """
        :type root: Node
        :rtype: List[int]
        """
        res = []
        if root is None:
            return []
        for child in root.children:
            res.extend(self.postorder(child))
        res.append(root.val)
        return res