12.25-----递归

N 叉树的后序遍历：

"""
# Definition for a Node.
class Node:
    def __init__(self, val=None, children=None):
        self.val = val
        self.children = children
"""

class Solution:
    def postorder(self, root: 'Node') -> List[int]:

        ans=[]
        def dfs_find (root):
            # 终止条件
            if root==None:
                return
            # 保存前序
            
            # 遍历子节点
            for child in root.children:
                # 进入下一层
                dfs_find(child)
            ans.append(root.val)

        dfs_find(root)
        return ans

N 叉树的前序遍历

"""
# Definition for a No