一、590. N叉树的后序遍历

1.1、题目描述

1.2.1、递归

""" # Definition for a Node. class Node: def __init__(self, val, children): self.val = val self.children = children """ class Solution: def __init__(self) ->None: self.ret = [] def postorder(self, root: 'Node') -> List[int]: if not root: return [] self.postorderT(root) return self.ret def postorderT(self, root: 'Node') -> List[int]: if root.children: for child in root.children: self.postorder(child) if root: self.ret.append(root.val)

1.2.2、迭代

class Solution: def __init__(self) ->None: self.ret = [] def postorder(self, root: 'Node') -> List[int]: if not root: return [] que = [root] while que: node = que.pop() if node: self.ret.append(node.val) for child in node.children: que.append(child) # 逆序 return self.ret[::-1]