145. Binary Tree Postorder Traversal Total Submissions: 271797 Difficulty: Hard 提交网址: https://leetcode.com/problems/binary-tree-postorder-traversal/ Given a binary tree, return the postorder traversal of its nodes' values. For example:Given binary tr…

Given a binary tree, return the postorder traversal of its nodes' values. For example: Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [3,2,1]. Note: Recursive solution is trivial, could you do it iteratively? 经典题目,求二叉树的后序遍历的非递归方法,跟前序,中序,层序一样都需要用到栈,后序的…

Given a binary tree, return the postorder traversal of its nodes' values. Example: Input: [,,] \ / Output: [,,] Follow up: Recursive solution is trivial, could you do it iteratively? 方法一:利用两个栈s1,s2来实现,先将头结点入栈s1,从s1弹出栈顶节点记为cur,压入s2中,分别将cur的左右孩子压入s1,当s…

题目: Given a binary tree, return the postorder traversal of its nodes' values. Example: Input: [1,null,2,3] 1 \ 2 / 3 Output: [3,2,1] Follow up: Recursive solution is trivial, could you do it iteratively? 分析: 给定一棵二叉树,返回后序遍历. 递归方法很简单,即先访问左子树,再访问右子树,最后访…

这道题是LeetCode里的第145道题. 题目要求: 给定一个二叉树,返回它的 后序 遍历. 示例: 输入: [1,null,2,3] 1 \ 2 / 3 输出: [3,2,1] 进阶: 递归算法很简单,你可以通过迭代算法完成吗? 解题代码: /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x)…

题目: Given a binary tree, return the postorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [3,2,1]. Note: Recursive solution is trivial, could you do it iteratively? 说明: 1) 两种实现,递归与非递归 , 其中非递归有两种方法 2)复杂度分析…

给定一棵二叉树,返回其节点值的后序遍历.例如:给定二叉树 [1,null,2,3],   1    \     2    /   3返回 [3,2,1].注意: 递归方法很简单,你可以使用迭代方法来解决吗?详见:https://leetcode.com/problems/binary-tree-postorder-traversal/description/ Java实现: 递归实现: /** * Definition for a binary tree node. * public class…

Given a binary tree, return the postorder traversal of its nodes' values. For example: Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [3,2,1]. Note: Recursive solution is trivial, could you do it iteratively? 经典题目,求二叉树的后序遍历的非递归方法,跟前序,中序,层序一样都需要用到栈,后续的…

题目: 二叉树的后序遍历 给出一棵二叉树,返回其节点值的后序遍历. 样例 给出一棵二叉树 {1,#,2,3}, 1 \ 2 / 3 返回 [3,2,1] 挑战 你能使用非递归实现么? 解题: 递归程序好简单 Java程序: /** * Definition of TreeNode: * public class TreeNode { * public int val; * public TreeNode left, right; * public TreeNode(int val) { * th…

给定一个二叉树,返回它的 后序 遍历. 进阶: 递归算法很简单,你可以通过迭代算法完成吗? 递归: class Solution { public: vector<int> res; vector<int> postorderTraversal(TreeNode* root) { if(root == NULL) return res; postorderTraversal(root ->left); postorderTraversal(root ->right);…