1classSolution {2public:3vector<int> postorderTraversal(TreeNode *root) {4vector<int>result;5stack<TreeNode *>s;6TreeNode *p =root;7TreeNode *q = nullptr, *last =nullptr;8while(!s.empty() ||p) {9if(p) {10s.push(
二叉树遍历(Binary Tree Traversal) 二叉树的递归遍历比较简单,这里说一下非递归遍历,以中序遍历为例子。 非递归遍历主要用到栈来协助进行。对于一个二叉树,首先根节点入栈,如果有左儿子,则继续入栈,重复直到最左边的儿子,这时候此节点值为要遍历的第一个值,他父亲是在栈顶。所以我们做一次出栈操作 f = stack...
add(root.val); traversal(root.right); } } 复杂度分析 时间复杂度:O(n),其中 n 是二叉树的节点数。每一个节点恰好被遍历一次 空间复杂度:O(n),为递归过程中栈的开销,平均情况下为 O(logn),最坏情况下树呈现链状,为 O(n) 递归法 /** * Definition for a binary tree node. * public ...
Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level). Example 1: Input: root = [3,9,20,null,null,15,7] Output: [[3],[9,20],[15,7]] Example 2: Input: root = [1] Output: [[1]] Example ...
Implementation of Inorder, Preorder, and Postorder traversal or a binary tree / binary search tree. Learn to implement binary tree traversal methods: Inorder, Preorder, and Postorder. Code examples are provided for traversing nodes in specific orders in
Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example: Given binary tree [3,9,20,null,null,15,7], 代码语言:javascript 代码运行次数:0 运行 AI代码解释 ...
return its bottom-up level order traversal as: [[15,7],[9,20],[3]] 1. 2. 3. 4. 5. 题目大意 按层序从下到上遍历一颗树。 解题思路 用一个队列即可实现。 参考代码 packageleetcodeimport("/halfrost/LeetCode-Go/structures")// TreeNode definetypeTreeNode=structures.TreeNode/** ...
1 struct TreeNode { 2 int val; 3 TreeNode* left; 4 TreeNode* right; 5 TreeNode(int x): val(x), left(NULL),right(NULL) {} 6 }; 7 8 void Swap(vector<int> &ivec) 9 { 10 int temp = 0; 11 int len = ivec.size(); 12 for (int i = 0; i < len/2; i ++) { 13...
Tree traversalis the process of visiting each node in the tree exactly once. Visiting each node in a graph should be done in a systematic manner. If search result in a visit to all the vertices, it is called a traversal. There are basically three traversal techniques for a binary tree th...
If we are given a binary tree and we need to perform a vertical order traversal, that means we will be processing the nodes of the binary tree from left to right. Suppose we have a tree such as the one given below. If we traverse the tree in vertical order and print the nodes then...