[leetcode]1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree 链接 leetcode 描述   Given two binary trees original and cloned and given a reference to a node target in the original tree.   The cloned tree is a copy of the original tr…

这是悦乐书的第285次更新,第302篇原创 01 看题和准备 今天介绍的是LeetCode算法题中Easy级别的第153题(顺位题号是671).给定非空的特殊二叉树,其由具有非负值的节点组成,其中该树中的每个节点具有恰好两个或零个子节点. 如果节点具有两个子节点,则该节点的值是其两个子节点中的较小值.给定这样的二叉树,您需要输出由整个树中所有节点的值组成的集合中的第二个最小值.如果不存在这样的第二个最小值,则输出-1.例如: 2 / \ 2 5 / \ 5 7 输出:5 2 / \ 2 2 输出…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 找出所有值再求次小值 遍历时求次小值 日期 题目地址:https://leetcode.com/problems/second-minimum-node-in-a-binary-tree/description/ 题目描述 Given a non-empty special binary tree consisting of nodes with t…

题目在这里,要求一个二叉树的倒数第二个小的值.二叉树的特点是父节点的值会小于子节点的值,父节点要么没有子节点,要不左右孩子节点都有. 分析一下,根据定义,跟节点的值肯定是二叉树中最小的值,剩下的只需要找到左右子树中比跟节点大的最小值就可以了.对于这个题目,还是考察的二叉树的搜索,第一印象是BFS.使用一个辅助队列存储遍历过程中的节点,遍历过程中,如果节点的值比结果中第二小的值还大,就不用继续把该节点及其所有的子节点入队了,这样可以节省时间.这里的辅助队列使用的是deque,在两端存取数据的复杂度…

1.题目描述 2.问题分析 使用set. 3.代码 set<int> s; int findSecondMinimumValue(TreeNode* root) { dfs(root); vector<int> v; for (set<int>::iterator it = s.begin(); it != s.end(); it++) { v.push_back(*it); } sort(v.begin(), v.end()); ? v[] : -; } void d…

乘风破浪:LeetCode真题_019_Remove Nth Node From End of List 一.前言 这次总算到了链表的操作了,之后肯定会有排序算法,二叉树,排序树,图等等的操作,现在我们先从链表开始. 二.Remove Nth Node From End of List 2.1 问题 2.2 分析与解决 其实这个问题真的不难,只要知道了链表的长度,然后做一个减法就能找到需要移除的节点了,但是题目上说可以在一次遍历之内就完成运算吗?这就有点难度了,我们可能一时想不开,作为单向链表,…

671. 二叉树中第二小的节点 671. Second Minimum Node In a Binary Tree 题目描述 给定一个非空特殊的二叉树,每个节点都是正数,并且每个节点的子节点数量只能为 2 或 0.如果一个节点有两个子节点的话,那么这个节点的值不大于它的子节点的值. 给出这样的一个二叉树,你需要输出所有节点中的第二小的值.如果第二小的值不存在的话,输出 -1. 每日一算法2019/5/12Day 9LeetCode671. Second Minimum Node In a Bin…

leetcode面试准备:Lowest Common Ancestor of a Binary Search Tree & Binary Tree 1 题目 Binary Search Tree的LCA Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. According to the definition of LCA on Wikiped…

Leetcode之广度优先搜索(BFS)专题-133. 克隆图(Clone Graph) BFS入门详解:Leetcode之广度优先搜索(BFS)专题-429. N叉树的层序遍历(N-ary Tree Level Order Traversal) 给定无向连通图中一个节点的引用,返回该图的深拷贝(克隆).图中的每个节点都包含它的值 val(Int) 和其邻居的列表(list[Node]). 示例: 输入: {"$id":"1","neighbors&quo…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 DFS 日期 题目地址:https://leetcode.com/problems/sum-of-root-to-leaf-binary-numbers/ 题目描述 Given a binary tree, each node has value 0 or 1. Each root-to-leaf path represents a binary n…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 DFS BFS 日期 题目地址:https://leetcode.com/problems/vertical-order-traversal-of-a-binary-tree/ 题目描述 Given a binary tree, return the vertical order traversal of its nodes values. For…

[LeetCode]863. All Nodes Distance K in Binary Tree 解题报告(Python) 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址:https://leetcode.com/problems/all-nodes-distance-k-in-binary-tree/description/ 题目描述: We are given a binary tree (with root no…

[LeetCode]331. Verify Preorder Serialization of a Binary Tree 解题报告(Python) 标签: LeetCode 题目地址:https://leetcode.com/problems/verify-preorder-serialization-of-a-binary-tree/description/ 题目描述: One way to serialize a binary tree is to use pre-order traver…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 日期 题目地址:https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/description/ 题目描述 Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in…

LeetCode 81 Search in Rotated Sorted Array II [binary search] <c++> 给出排序好的一维有重复元素的数组,随机取一个位置断开,把前半部分接到后半部分后面,得到一个新数组,在新数组中查找给定数是否存在,时间复杂度限制\(O(log_2n)\) C++ 因为有重复元素存在,nums[l] <= nums[mid]不能说明[l,mid]区间内一定是单调的,比如数组[1,2,3,1,1,1,1],但是严格小于和严格大于的情况还是可以…

85. Insert Node in a Binary Search Tree Given a binary search tree and a new tree node, insert the node into the tree. You should keep the tree still be a valid binary search tree. Example Example 1: Input: tree = {}, node = 1 Output: 1 Explanation:…

Given a binary search tree and a new tree node, insert the node into the tree. You should keep the tree still be a valid binary search tree. Example Given binary search tree as follow: 2 / \ 1 4 / 3 after Insert node 6, the tree should be: 2 / \ 1 4…

Given a binary search tree and a new tree node, insert the node into the tree. You should keep the tree still be a valid binary search tree. Notice You can assume there is no duplicate values in this tree + node.   Example Given binary search tree as…

Leetcode之二分法专题-704. 二分查找(Binary Search) 给定一个 n 个元素有序的(升序)整型数组 nums 和一个目标值 target  ,写一个函数搜索 nums 中的 target,如果目标值存在返回下标,否则返回 -1. 示例 1: 输入: nums = [-1,0,3,5,9,12], target = 9 输出: 4 解释: 9 出现在 nums 中并且下标为 4 示例 2: 输入: nums = [-1,0,3,5,9,12], target = 2 输出:…

problem 671. Second Minimum Node In a Binary Tree 参考 1. Leetcode_easy_671. Second Minimum Node In a Binary Tree; 完…

Given a non-empty special binary tree consisting of nodes with the non-negative value, where each node in this tree has exactly two or zero sub-node. If the node has two sub-nodes, then this node's value is the smaller value among its two sub-nodes.…

一天一道LeetCode系列 (一)题目 Given a linked list, remove the nth node from the end of list and return its head. For example, Given linked list: 1->2->3->4->5, and n = 2. After removing the second node from the end, the linked list becomes 1->2->…

Given a non-empty special binary tree consisting of nodes with the non-negative value, where each node in this tree has exactly two or zero sub-node. If the node has two sub-nodes, then this node's value is the smaller value among its two sub-nodes.…

原题链接在这里:https://leetcode.com/problems/second-minimum-node-in-a-binary-tree/description/ 题目: Given a non-empty special binary tree consisting of nodes with the non-negative value, where each node in this tree has exactly two or zero sub-node. If the n…

https://leetcode.com/problems/remove-nth-node-from-end-of-list/ 原题: Given a linked list, remove the nth node from the end of list and return its head. For example, Given linked list: 1->2->3->4->5, and n = 2. After removing the second node fro…

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up: What if the linked list is extremely large and its length is unknown to you? Could you solve this effi…

原题链接在这里:https://leetcode.com/problems/maximum-difference-between-node-and-ancestor/ 题目: Given the root of a binary tree, find the maximum value V for which there exists different nodes A and B where V = |A.val - B.val| and A is an ancestor of B. (A n…

题目如下: We are given a linked list with head as the first node.  Let's number the nodes in the list: node_1, node_2, node_3, ... etc. Each node may have a next larger value: for node_i, next_larger(node_i) is the node_j.val such that j > i, node_j.val…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 单调递减栈 日期 题目地址:https://leetcode.com/problems/next-greater-node-in-linked-list/ 题目描述 We are given a linked list with head as the first node. Let's number the nodes in the list: no…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 个人公众号:负雪明烛 本文关键词:链表, 删除节点,双指针,题解,leetcode, 力扣,Python, C++, Java 目录 题目描述 题目大意 解题方法 双指针 日期 题目地址:https://leetcode.com/problems/remove-nth-node-from-end-of-list/description/ 题目描述 Given a linked list,…