Given a binary tree, return the inorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? confused what "{1,#,2,3}" means? > re…

题目大意 https://leetcode.com/problems/binary-tree-inorder-traversal/description/ 94. Binary Tree Inorder Traversal Given a binary tree, return the inorder traversal of its nodes' values. Example: Input: [1,null,2,3] 1 \ 2 / 3 Output: [1,3,2] Follow up:…

Given a binary tree, return the inorder traversal of its nodes' values. Example: Input: [,,] \ / Output: [,,] Follow up: Recursive solution is trivial, could you do it iteratively? 题目中要求使用迭代用法,利用栈的“先进后出”特性来实现中序遍历. 解法一:(迭代)将根节点压入栈,当其左子树存在时,一直将其左子树压入栈,…

这道题是LeetCode里的第94道题. 题目要求: 给定一个二叉树,返回它的中序 遍历. 示例: 输入: [1,null,2,3] 1 \ 2 / 3 输出: [1,3,2] 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) :…

给定一个二叉树,返回它的中序 遍历. 示例: 输入: [1,null,2,3] 1 \ 2 / 3 输出: [1,3,2] 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> inorderTraversal(TreeNode* root) { if(root == NULL) return res; if(root ->left != NULL) { inor…

二叉树遍历(前序.中序.后序.层次.深度优先.广度优先遍历) 描述 解析 递归方案 很简单,先左孩子,输出根,再右孩子. 非递归方案 因为访问左孩子后要访问右孩子,所以需要栈这样的数据结构. 1.指针指向根,根入栈,指针指向左孩子.把左孩子当作子树的根,继续前面的操作. 2.如果某个节点的左孩子不存在,节点出栈,指针指向节点的右孩子.把这个右节点当作根, 继续前面的操作. 代码 /** * Definition for a binary tree node. * public class Tre…

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…

Given a binary tree, return the preorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [1,2,3]. Note: Recursive solution is trivial, could you do it iteratively? 一般我们提到树的遍历,最常见的有先序遍历,中序遍历,后序遍历和层序遍历,它们用递归实现起…

Given a binary tree, return the preorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [1,2,3]. Note: Recursive solution is trivial, could you do it iteratively? 树的遍历,最常见的有先序遍历,中序遍历,后序遍历和层序遍历,它们用递归实现起来都非常的简…

Given a binary tree, return the inorder traversal of its nodes' values. For example:Given binary tree{1,#,2,3}, 1 \ 2 / 3 return[1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? confused what"{1,#,2,3}"means? > read m…