【Leetcode】简单题：二叉树的后序遍历

二叉树的后序遍历

给你一棵二叉树的根节点 root ，返回其节点值的 后序遍历 。

AC代码

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def postorderTraversal(self, root: Optional[TreeNode]) -> List[int]:
        def traival(root:TreeNode):
            if not root:
                return
            else:
                traival(root.left)
                traival(root.right)
                res.append(root.val)
        
        res = []
        traival(root)
        return res

官方代码

class Solution:
    def postorderTraversal(self, root: TreeNode) -> List[int]:
        def postorder(root: TreeNode):
            if not root:
                return
            postorder(root.left)
            postorder(root.right)
            res.append(root.val)
        
        res = list()
        postorder(root)
        return res


# 作者：LeetCode-Solution

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