815. 公交路线 我们有一系列公交路线.每一条路线 routes[i] 上都有一辆公交车在上面循环行驶.例如,有一条路线 routes[0] = [1, 5, 7],表示第一辆 (下标为0) 公交车会一直按照 1->5->7->1->5->7->1->- 的车站路线行驶. 假设我们从 S 车站开始(初始时不在公交车上),要去往 T 站. 期间仅可乘坐公交车,求出最少乘坐的公交车数量.返回 -1 表示不可能到达终点车站. 示例: 输入: routes = [[1,…

606. 根据二叉树创建字符串 你需要采用前序遍历的方式,将一个二叉树转换成一个由括号和整数组成的字符串. 空节点则用一对空括号 "()" 表示.而且你需要省略所有不影响字符串与原始二叉树之间的一对一映射关系的空括号对. 示例 1: 输入: 二叉树: [1,2,3,4] 1 / \ 2 3 / 4 输出: "1(2(4))(3)" 解释: 原本将是"1(2(4)())(3())", 在你省略所有不必要的空括号对之后, 它将是"1(2(4…

本文总结LeetCode上有关深度优先搜索(DFS).广度优先搜索(BFS)和回溯法的算法题,推荐刷题总数为13道.具体考点分析如下图: 一.深度优先搜索 1.字符匹配问题 题号:301. 删除无效的括号,难度困难 2.数组或字符串问题 题号:329. 矩阵中的最长递增路径,难度困难 题号:488. 祖玛游戏,难度困难 题号:491. 递增子序列,难度中等 3.特定场景应用问题 题号:679. 24 点游戏,难度困难 题号:1254. 统计封闭岛屿的数目,难度中等 二.广度优先搜索 1.数组或字…

We have a list of bus routes. Each routes[i] is a bus route that the i-th bus repeats forever. For example if routes[0] = [1, 5, 7], this means that the first bus (0-th indexed) travels in the sequence 1->5->7->1->5->7->1->... forever…

自从计算机软件开发进入网络时代,就开始涉及到通讯问题.在客户/服务器(也叫C/S应用)时期,每个软件都有自己的客户端和服务器端软件.并且客户端和服务器端之间的通讯协议差别也很大.后来随着互联网的发展,基于浏览器/服务器的应用逐渐成为主流,通讯协议也统一到HTTP协议.但是,在HTTP协议之上,如何处理来自客户端的请求信息,以及如何对请求进行回应,则经历了很长时间也没有统一下来.目前,对于这个问题的解决方案主要有两种,一个是CGI,另一个是Servlet. CGI(Common Gateway I…

一.问题描述 基于百度地图实现检索指定城市指定公交的交通路线图,效果如图所示 二.通用组件Application类,主要创建并初始化BMapManager public class App extends Application { static App mDemoApp; //百度MapAPI的管理类 public BMapManager mBMapMan = null; // 授权Key // 申请地址:http://dev.baidu.com/wiki/static/imap/key/ p…

We have a list of bus routes. Each routes[i]is a bus route that the i-th bus repeats forever. For example if routes[0] = [1, 5, 7], this means that the first bus (0-th indexed) travels in the sequence 1->5->7->1->5->7->1->... forever.…

百度开放的公交路线的链接,IE跳转会出现中文变成乱码的问题.如图: //创建InfoWindow function createInfoWindow() { var desDiv = []; desDiv.push("<b style='color: #CC5522;font-size: 14px;font-weight: bold;overflow: hidden;padding-right: 13px;white-space: nowrap;' class='iw_poi_title'…

创建关系映射文件:(把实体类映射成一个表) 1 右键src==>new==>other==>hibernate==>hbm.xml==>Student==>Finish 2 创建mysql数据库 <?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http…

JAVA String对象和字符串常量的关系解析 1 字符串内部列表 JAVA中所有的对象都存放在堆里面,包括String对象.字符串常量保存在JAVA的.class文件的常量池中,在编译期就确定好了. 虚拟机为每个被装载的类型维护一个常量池.常量池就是该类型所用常量的一个有序集合,包括直接常量(string.integer和float point常量)和对其他类型.字段和方法的符号引用. 例如, String s = new String( "myString" ); 其中字符串常量…

Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers. Ensure that numbers within the set are sorted in ascending order. Example 1…

Given a string S, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can find by performing this transformation. For example: Given "aacecaaa", return "aaacecaaa&qu…

Given a 2D board and a list of words from the dictionary, find all words in the board. Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same le…

Design a data structure that supports the following two operations: void addWord(word)bool search(word) search(word) can search a literal word or a regular expression string containing only letters a-z or .. A . means it can represent any one letter.…

There are a total of n courses you have to take, labeled from 0 to n - 1. Some courses may have prerequisites, for example to take course 0 you have to first take course 1, which is expressed as a pair: [0,1] Given the total number of courses and a l…

Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by…

Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may complete at most k transactions. 解题思路: https://leetcode.com/discuss/18330/is-it-best-solution-with-o-n-o-1…

Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). Find the minimum element. The array may contain duplicates. 解题思路: 参考Java for LeetCode 081 Search in Rotated Sorted Array II J…

Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). Find the minimum element. You may assume no duplicate exists in the array. 解题思路: 本题和Java for LeetCode 033 Search in Rotated S…

The set [1,2,3,…,n] contains a total of n! unique permutations. By listing and labeling all of the permutations in order, We get the following sequence (ie, for n = 3): "123" "132" "213" "231" "312" "…

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example, Given n = 3, You should return the following matrix: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ]] 解题思路: 参考Java for LeetCode 054 Spiral Matrix,修改下…

Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary). You may assume that the intervals were initially sorted according to their start times. Example 1: Given intervals [1,3],[6,9], insert and merge…

Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maximum jump length at that position. Determine if you are able to reach the last index. For example: A =…

Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example, [1,1,2] have the following unique permutations: [1,1,2], [1,2,1], and [2,1,1]. 解题思路一: 发现Java for LeetCode 046 Permutations自己想多了,代码直接拿来用…

Implement wildcard pattern matching with support for '?' and '*'. '?' Matches any single character. '*' Matches any sequence of characters (including the empty sequence). The matching should cover the entire input string (not partial). The function p…

Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring. For "(()", the longest valid parentheses substring is "()", which has length = 2. Another example is &…

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 解题思路一: 之前我们有mergeTwoLists(ListNode l1, ListNode l2)方法,直接调用的话,需要k-1次调用,每次调用都需要产生一个ListNode[],空间开销很大.如果采用分治的思想,对相邻的两个ListNode进行mergeTwoLists,每次将规模减少一半,直到…

最近跟着百度地图API学地图开发,先是学了路径搜索,对于已知坐标的两点进行驾车.公交.步行三种路径的搜索(公交路径运行没效果,待学习中),后来又 学了定位功能,能够获取到自己所在位置的经纬度,但当将两者合起来先自动获取自己所在位置的经纬度然后与固定地点进行路径搜索时却弄不出来了,因为刚开始 写的两者在两个类中总是取不到经纬度值,后来将两者写到同一个类中去了,终于取到经纬度值了,也运行出来了.需要 在 BDLocationListener的onReceiveLocation里获取到经纬度值,因为已…

题意: 给若干景点,每个景点有若干单向边到达其他景点,要求规划一下公交路线,使得每个景点有车可达,并且每个景点只能有1车经过1次,公车必须走环形回到出发点(出发点走2次).问是否存在这样的线路?若存在就给出所有公交车需要走过的路的长度,要求长度尽量小. 分析: 这超级难发现是网络流来做的.要将每个点归结到某个环上,那么环上的点都是只有1个前驱,1个后继.如果1个前驱配1个后继,就是匹配问题了.但是这样的匹配有点混杂,所以要拆点,将1个点拆成2个,分别处于X和Y集中,然后根据有向边建图.成了带权二…

根据自己的学习体会并参考了一些网上的资料,以java写出了二叉树的创建.搜索.删除和遍历等操作,尚未实现的功能有:根据先序和中序遍历,得到后序遍历以及根据后序和中序遍历,得到先序遍历,以及获取栈的深度和其它的一些方法等完成了再继续更新: 二叉树的java实现: package com.peter.java.dsa.common; import java.util.ArrayList; public class BinaryTree { private TreeNode root; private…