zhanghaodx082的专栏

题目意思：  Given a singly linked list L: L0→L1→…→Ln-1→Ln,  eorder it to: L0→Ln→L1→Ln-1→L2→Ln-2→…  You must do this in-place without altering the nodes' values.  For example,  Given {1,2,3,4}, reorder

题目大意: Given a string s and a dictionary of words dict, add spaces in s to construct a sentence where each word is a valid dictionary word. Return all such possible sentences. For example, given

题目大意: A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. 意思就是:

题目大意: Given an array where elements are sorted in ascending order, convert it to a height balanced BST. 意思就是: 同Convert Sorted List to Binary Search Tree,只是把

题目大意: Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. 意思就是: 给定一棵二叉树,找到它的最短

题目大意: Path Sum

题目大意: Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root). For example: Given binary tree {3,9,20,#,#,

题目大意: Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node nev

题目大意: Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example: Given the below binary tree and sum = 22, 5 /

题目大意: Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. 意思就是

题目大意: Given a string S and a string T, count the number of distinct subsequences of T in S. A subsequence of a string is a new string which is formed from the original string by deleting some (ca

题目大意: Given a binary tree, flatten it to a linked list in-place. For example, Given 1 / \ 2 5 / \ \ 3 4 6 The flattened tree should look like: 1

题目大意: Given a binary tree struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; } Populate each next pointer to point to its next right nod

题目意思：看一个链表中是否有环。注：不能用额外的空间。 Given a linked list, determine if it has a cycle in it. Follow up: Can you solve it without using extra space? 解决思路： 1,首先，如果能用额外的空间，可以把访问过的节点存储到vector中，然后判断是否有重复，如果有

题目意思:

补充知识——前缀，中缀，后缀表达式的含义以及用计算几如何求前缀和后缀表达式的值。见我的收藏——“前缀、中缀、后缀表达式”。 做题思路： 1,Reverse Polish Notation是后缀表达式 2,根据收藏的文章，该算法用到的主要数据结构是栈。   前缀表达式的计算机求值： 从右至左扫描表达式，遇到数字时，将数字压入堆栈，遇到运算符时，弹出栈顶的两个数，用运算符对它们做相应的计算（

1,题目意思：在二维平面中，求在一条直线上的点的最大数目 2,做题思路：    两层嵌套循环实现，斜率相同的点即为在一条直线上的点，求得最大点数。     需要注意的是：     1）只有一个点时，直接返回1 ; 没有点时，要返回0，因此需要初始化max_num = 0。     2）最里面的循环分三种情况，第一，两个点相同时。第二，垂直于x轴时，斜率不存在。第三，其他，即普通情况。

题目大意: Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors. OJ's undirected graph serialization: Nodes are labeled uniquely. We use # as a separator