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RSS订阅原创 SDL实现生产者消费者
环境：阿里云主机CPU： 1核 内存： 1GB 数据盘： 20G操作系统： Ubuntu 12.04 64位 1. SDL安装[root@iZ25ml7xjj1Z:/usr/lixian]$sudo aptitude install libsdl1.2debian 2. 生产者消费者源代码
2014-11-03 20:12:23
1143
原创 3Sum
Problem:Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.Note:Elements in a tr
2014-10-27 09:43:19
407
原创 Generate Parentheses
Problem:Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, given n = 3, a solution set is:"((()))", "(()())", "(())()", "
2014-10-25 11:36:35
459
原创 Merge k Sorted Lists
Problem:Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.采用分治来做。两两合并链表，直到只剩下1个链表。时间复杂度为O(m*n*log(n))，而顺序合并的时间复杂度为O(m*n^2)。Solution:
2014-10-24 23:25:36
433
原创 Implement strStr()
Problem:Implement strStr().Returns a pointer to the first occurrence of needle in haystack, or null if needle is not part of haystack.我实现了Boyer-Moore算法，效果非常好，12ms就跑下来了。BM算法的效率非常高，优于KMP算法。算
2014-10-23 21:11:38
414
原创 Search for a Range
Problem:Given a sorted array of integers, find the starting and ending position of a given target value.Your algorithm's runtime complexity must be in the order of O(log n).If the target
2014-10-15 15:54:59
400
原创 Search Insert Position
Problem:Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.You may assume no duplicates
2014-10-15 14:28:11
386
原创 Sudoku Solver
Problem：Write a program to solve a Sudoku puzzle by filling the empty cells.Empty cells are indicated by the character '.'.You may assume that there will be only one unique solution.
2014-10-15 10:05:37
483
原创 Count and Say
Problem:The count-and-say sequence is the sequence of integers beginning as follows:1, 11, 21, 1211, 111221, ...1 is read off as "one 1" or 11.11 is read off as "two 1s" or 21.21 i
2014-10-14 11:13:09
423
原创 Combination Sum II
Problem：Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.Each number in C may only be used once
2014-10-14 10:31:26
435
转载 UML类图与类的关系详解
UML类图与类的关系详解在画类图的时候，理清类和类之间的关系是重点。类的关系有泛化(Generalization)、实现（Realization）、依赖(Dependency)和关联(Association)。其中关联又分为一般关联关系和聚合关系(Aggregation)，合成关系(Composition)。下面我们结合实例理解这些关系。基本概念
2014-10-14 09:09:06
521
原创 Combination Sum
Problem:Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.The same repeated number may be chosen from C
2014-10-13 22:32:50
529
原创 京东2015校招笔试编程题
这道题就是丑数问题，在《剑指Offer》一书的182页有详细讨论。简单来说，就是：新的丑数总是以前的某个丑数乘以2、3或5产生，那么分别用三个指针p2、p3和p5指向乘以2、3和5后能生成新的丑数的丑数，那么下一个丑数就是它们生成的新的丑数中最小的一个。public static int KthNumber(int k){ int[] uglyNumbers = new
2014-10-11 23:00:11
875
原创 First Missing Positive
Problem:Given an unsorted integer array, find the first missing positive integer.For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2.Your algorithm should run in O(n) time and
2014-10-11 09:12:26
374
原创 Trapping Rain Water
Problem:Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining.For example, Given [0,1,0,2,1,
2014-10-10 21:32:06
429
原创 Multiply Strings
Problem:Given two numbers represented as strings, return multiplication of the numbers as a string.Note: The numbers can be arbitrarily large and are non-negative. 大数乘法，通常采用的是模拟手工计算的方法，时
2014-10-10 15:50:02
360
转载 JSON解析工具-org.json使用教程
一、简介 org.json是Java常用的Json解析工具，主要提供JSONObject和JSONArray类，现在就各个类的使用解释如下。 二、准备 1.在使用org.json之前，我们应该先从该网址https://github.com/douglascrockford/JSON-java下载org.json源码，并将源码其加入到Eclipse中，
2014-10-10 10:18:02
446
原创 重写equals方法
equals方法用于判断当前对象this与另一个对象obj是否相等。必须遵守的规则：• 对称性：如果x.equals(y)返回是“true”，那么y.equals(x)也应该返回是“true”。 • 反射性：x.equals(x)必须返回是“true”。 • 类推性：如果x.equals(y)返回是“true”，而且y.equals(z)返回是“true”，那么z.equa
2014-10-10 10:15:10
453
翻译 CloudSim类设计
BwProvisioner: 这个抽象类为VM的带宽配置策略建模。该模块的主要功能是向在数据中心部署的相互竞争的VM分配网络带宽。云系统开发者可以用他们自己的策略（优先级，QoS）来扩展该类。BwProvisioningSimple允许VM根据需求尽可能多的保留带宽，但是会受到托管主机的总可用带宽限制。CloudCoordinator: 这个抽象类把一个云数据中心扩展到联盟，负责周期性监测
2014-10-10 10:13:41
1448
原创 重写hashCode方法
hashCode方法在Object类中定义如下：public native int hashCode();说明是一个本地方法，其实现和本地机器相关。我们可以在自己的类中覆盖hashCode方法。下面String类中重写的hashCode方法：public int hashCode() { int h = hash; if (h == 0) {
2014-10-10 10:13:25
1966
翻译 CloudSim内核仿真框架
GridSim是CloudSim的构件之一。GridSim使用SimJava库作为事件处理和实体间的消息传递的框架。SimJava在搭建可扩展的仿真环境时存在局限性。比如：它不允许在运行时通过编程重置仿真环境。它不支持在运行时创建新的仿真实体。随着系统规模的扩展，SimJava的多线程属性会带来性能上的开销。性能的下降是由线程间过度的上下文切换导致的。多线程处理会使
2014-10-10 10:11:57
919
原创 使用EclEmma进行覆盖测试
EclEmma是一个开源 Java 覆盖测试工具。进入下面的链接按提示安装集成到Eclipse中。http://www.eclemma.org/installation.html安装完成后，就可以在Eclipse的tool menu中看到EclEmma的icon了。单击此按钮，选择事先写好的JUnit test程序，就可以对代码进行覆盖测试了。测试完成后
2014-10-10 10:07:32
694
原创 XML转JSON
依赖的包：org.json.jar，commons-io-2.2.jar获取xml文件的InputStream is，使用IOUtils把is转成String。调用XML的toJSONObject方法获取JSON对象。import org.apache.commons.io.IOUtils;import org.json.*;InputStream
2014-10-10 10:06:03
820
原创 Eclipse 远程调试
在远程服务器上执行命令：root@raspberrypi:/home/cheng# java -Xdebug -Xrunjdwp:transport=dt_socket,server=y,address="8000" -jar cli.jar 在本地Eclipse中选中调试的项目，右键选择Debug as->Debug Configurations，出现Debug C
2014-10-10 09:59:25
509
原创 卸载MySQL，安装SQLite
卸载MySQL：#sudo apt-get autoremove --purge mysql-server-5.0出现是否继续选项时，选yDo you want to continue [Y/n]? y出现warning，可以卸载完成后手动删除/etc/mysql。dpkg: warning: while removing mysql-common, direc
2014-10-10 09:56:20
1012
原创 Wildcard Matching
Problem:Implement wildcard pattern matching with support for '?' and '*'.'?' Matches any single character.'*' Matches any sequence of characters (including the empty sequence).The matching
2014-10-10 09:48:12
287
原创 Jump Game II
Problem: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.
2014-10-09 20:43:31
476
原创 亚马逊2015校招在线笔试2
import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.util.Arrays;import java.util.HashMap;public class AmazonOnline2 {public static voi
2014-10-09 17:23:39
1206
原创 Permutations II
Problem: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],
2014-10-09 13:50:03
396
原创 Permutations
Problem:Given a collection of numbers, return all possible permutations.For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1].
2014-10-09 13:25:26
735
原创 亚马逊2015校招在线笔试1
截图有重叠，大家将就一下。本人没有参加在线笔试，主要跟大家分享一下思路。 题目的意思就是找到从起始节点开始的定长路径，路径必须包含一个必须要到达的节点。返回所有的路径数，如果不存在这样的路径，则返回0。 既然要找到所有路径，那就采用广搜。如果路径长度达到指定长度，则检查路径中是否包含必须要到达的节点，如果包含，路径数加1；如果路径长度没有达到指定长度，则从当前路径的末节
2014-10-09 12:39:23
1211
原创 Rotate Image
Problem:You are given an n x n 2D matrix representing an image.Rotate the image by 90 degrees (clockwise).Follow up:Could you do this in-place? 就是求矩阵的转置，如果不计空间复杂度，新建一个矩阵，按行复制到列就行了
2014-10-08 16:35:05
326
原创 N-Queens
Problem:The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other.Given an integer n, return all distinct solutions to the n-
2014-10-08 10:19:40
342
原创 Jump Game
Problem: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.
2014-10-07 21:08:37
427
原创 Merge Intervals
Problem:Given a collection of intervals, merge all overlapping intervals.For example,Given [1,3],[2,6],[8,10],[15,18],return [1,6],[8,10],[15,18].先根据start按升序排序，再依序合并重叠区间。为了节省空间，实现
2014-10-07 20:31:52
382
原创 Insert Interval
Problem: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 sta
2014-10-07 16:42:42
406
原创 Rotate List
Problem:Given a list, rotate the list to the right by k places, where k is non-negative.For example:Given 1->2->3->4->5->NULL and k = 2,return 4->5->1->2->3->NULL.移动p,q指针到下图所示的位置。然
2014-10-07 12:19:31
378
原创 Unique Paths II
Problem:Follow up for "Unique Paths":Now consider if some obstacles are added to the grids. How many unique paths would there be?An obstacle and empty space is marked as 1 and 0 respecti
2014-10-07 09:53:33
369
原创 Unique Paths
Problem:A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below).The robot can only move either down or right at any point in time. The robot is trying
2014-10-06 23:28:06
355
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