I posted this question on Stack Overflow today because the complete life cycle of a simple program is interesting. I will keep updating the post by using answers/comments to make it more complete and correct my mistake. I surely will up vote any answer/comment that makes sense. Please up vote or post answer/comment to help. … Read more
Given a garden with N slots. In each slot, there is a flower. Each of the N flowers will bloom one by one in N days. In each day, there will be exactly one flower blooming and it will stay blooming since then. Given an array of numbers from 1 to N. Each number in … Read more
Implement a MyCalendarTwo class to store your events. A new event can be added if adding the event will not cause a triple booking. Your class will have one method, book(int start, int end). Formally, this represents a booking on the half open interval [start, end), the range of real numbers x such that start
In many articles, developers have compared Swing with SWT with a lot of details. However, there is not a side-by-side comparison by using a diagram which may give a direct impression of how they are different. In this post, I will compare Swing and SWT side by side and get a taste of the difference … Read more
This post also assumes that you have a standalone Eclipse RCP application. You can find out how to make one here. You may have tried some free tools to generate tag cloud or text cloud, but they may not exactly what you want. As a Java programmer, you can quickly implement such a function by … Read more
If you don’t want to use latex or metapost to plot your research data, Java is also good for that. We can use SWT to draw those points on axis or any positions on a panel, and this can be done very quickly. First of all, you need to use eclipse RCP wizard to create … Read more
Given a time represented in the format “HH:MM”, form the next closest time by reusing the current digits. There is no limit on how many times a digit can be reused. You may assume the given input string is always valid. For example, “01:34”, “12:09” are all valid. “1:34”, “12:9” are all invalid. Example 1: … Read more
Given a rows x cols screen and a sentence represented by a list of non-empty words, find how many times the given sentence can be fitted on the screen. Note: A word cannot be split into two lines. The order of words in the sentence must remain unchanged. Two consecutive words in a line must … Read more
You may use CVS daily for your program, but never touch the collaboration part. In fact, that is the most exciting part. In this tutorial, I will first briefly explain the concepts of trunk, branch and tags. And then use a real team collaboration example to demonstrate how cvs works. How CVS works? First of … Read more
Some developers have claimed that Python is more productive than Java. It is dangerous to make such a claim, because it may take several days to prove that thoroughly. From a high level view, Java is statically typed, which means all variable names have to be explicitly declared. In contrast, Python is dynamically typed, which … Read more
Eclipse version: Indigo Platform: Ubuntu 11.10 Error message: An error occurred while collecting items to be installed session context was:(profile=epp.package.java, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=). No repository found containing: osgi.bundle,javax.mail.glassfish,1.4.1.v201005082020 This is possibly caused by in compatible eclipse version. If we use Help -> Eclipse MarketPlace to install PyDev, the problem is gone.
Generic types are extensively used in Java collections. Why do we need Generic types in Java? Understanding this question can help us better understand a lot of related concepts. In this article, I will use a very short example to illustrate why Generic is useful. 1. Overview of Generics The goal of implementing Generics is … Read more
This post shows how to setup a python web development environment under Ubuntu and make a hello world example. So Python has become a hot word in recent years. But before you can do anything about it, you need a “hello world” sample application. In this post, I will build a hello world Python web … Read more
Github is a more popular and social code repository. It is the trend to be a user, at least it is true for now. There are a lot of problems we may meet, most of them can be solved by reading the documentation. But that is not fast or something we like to do. Problem … Read more
You may wonder what a Java class looks like as an Abstract Syntax Tree(AST). We can view AST of any Java class by using Eclipse ASTView. The AST can be easily showed in a separate view under eclipse IDE. For the following simple java class, the ASTView shows the complete AST. public class Test { … Read more