Stock market volatility continues unabated. It may be too early to tell, but I’m marking the top of this current market correction at July 20, with the bottom still to be determined (though I’d say it’s still a few weeks off). Since July 20, investor…

http://www.onjava.com/pub/a/onjava/2001/05/30/optimization.htmlComparing the performance of LinkedLists and ArrayLists (and Vectors) (Page last updated May 2001, Added 2001-06-18, Author Jack Shirazi, Publisher OnJava). Tips: ArrayList is faster than…

make no mistake, we are the last line of defense.…

As we all know, Matt is an outstanding contestant in ACM-ICPC. Graph problems are his favorite.Once, he came up with a simple algorithm for finding the maximal independent set in trees by mistake.A tree is a connected undirected graph without cycles,…

PHP Advanced and Object-Oriented Programming 3rd Edition Related to modularity is abstraction: classes should be defined broadly. This is a common and understandable beginner’s mistake. As an example, instead of designing a class for interacting with…

[common mistake of closure in loops] 下例中item引用的始终是最后一个值. function showHelp(help) { document.getElementById('help').innerHTML = help; } function setupHelp() { var helpText = [ {'id': 'email', 'help': 'Your e-mail address'}, {'id': 'name', 'help': 'You…

One of the top suggestions (currently #15 on uservoice) for improving C# is the addition of non-nullable reference types. This is not surprising, considering the number of functions that start with a block of ‘if (x == null) throw new ArgumentNullExc…

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原文作者: Roman Elizarov 原文地址: Null is your firend, not a mistake 译者:秉心说 Kotlin Island from Wikimedia by Pavlikhin, CC BY-SA 4.0 我使用 Java 语言编程已经很久很久了,掌握了通过 Java 编写和维护大型软件(百万行代码)应该注意些什么,并亲眼目睹了全行业都在竭力避免空指针异常 NullPointerException(NPE),它困扰着大大小小的 Java 类库.在 20…

Just A Mistake Time Limit: 5000/5000 MS (Java/Others)    Memory Limit: 512000/512000 K (Java/Others)Total Submission(s): 168    Accepted Submission(s): 41 Problem Description As we all know, Matt is an outstanding contestant in ACM-ICPC. Graph proble…