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Bao Jianqiang follow
Graduated from the Department of mathematics, Fudan University. Has in the company of much home Internet as wireless technology department director, trek in Android, IOS, WP, multi wireless technology in App item There are many years of practical experience in project management. He is a Microsoft MVP in 2008, author of "research and development of APP recorded: architecture design, crash analysis and competing products technical analysis", and adhere to a written six years of Technology Blog: Http://
Yao Qiang follow
Graduate of Beijing University of Posts and Telecommunications. On the big data machine learning / data mining has a strong interest, keen to use algorithms and machine learning data mining useful business letter Interest. Years experience in machine learning / data mining. Done NLP, text retrieval, recommendation system, click rate prediction, deep learning image classification / retrieval related projects. Willing to organize and share knowledge, to maintain good quality blog column, Ensure the quality of each blog.

Java source collection framework (Figure)

Baidu Java collection map, the search out of a map, a pretty good figure, and now to borrow it. Picture from:

Java source code Collection framework Set graph

Java source LinkedHashMap

Java source LinkedHashMap Reproduced please indicate the source: First, LinkedHashMap overview Map is the LinkedHashMap interface hash table and link list to achieve, with predictable iterative sequence. The difference between this implementation and HashMap is that LinkedHashMap maintains a list of double linked lists for all entries. This link list defines the iteration order, which is usually the order in which the key is inserted into the map...

Java source code LinkedHashMap

[OJ LeetCode 34] for a Range Search

Title Link: Title: a sorted array of integers Given find the starting and ending position of a given target value. Algorithm's runtime complexity must Your...

Java LeetCode

Boot MyBatis Spring connection database 专家

Recently quite was busy, before pumping time to be integrated to send out, in fact, mybatis official website in 2015 by the end of November has released the SpringBoot integrated the release version, GitHub Code: In front of the JPA and JDBC connection database to do a description, this paper is also a reference to the official code to do a summary. First say a digression, SpringBoot use the default org....


Java source Hashtable

Java source Hashtable First, Hashtable overview Class implements a hash table, the hash table will be mapped to the corresponding value value object key object. Requires key and value are not null. In order to successfully store and retrieve objects in a hash table, the hashCode method and the equals method must be implemented for the object to be used as a key. Hashtable is a thread synchronization, but the non threaded synchronization of HashMap can replace it. If not...

Java source code Hashtable

How to implement a real-time communication system: support PC and mobile terminals while online (i.e., support for multiple devices with multiple devices at the same time)? 专家

If we develop the instant messaging system (IM) system to support the same account equipment and login of the scene (or "to login), namely, the need to like QQ, PC login at the same time, also can (IOS or Android) using the same account login mobile side, what, how to do? ...

instant messaging Mobile terminal Multi login Multi device login

Memory leak detection in Linux (three) customized new/delete 专家

"Linux memory leak detection (two) customized malloc/free" in the __wrap method only to solve the problem of C, this section describes how to make new/delete C++ can also be easily inserted into the count code. Wrap method can try to use __wrap_new/__wrap_delete? Let's try it. I wrote this test code #include Namespace STD int; count using = 0; void...

Memory leak Linux

Memory leak detection in Linux (two) customized malloc/free 专家

The Linux memory leak detection (a) the simplest method, introduced the simple memory leak detection method, this method, although simple, but there are many practical problems, lead to it cannot be used for the actual production in. The direct use of this method is certainly not realistic, because: (1) the whole project where all the calls to malloc/free are changed to my_malloc/my_free, code changes a lot. (2) the code for the usual dynamic library and the static library is not authorized to modify the. Today to solve this problem, the dynamic decision to allow the program to use their own or the system...

Memory leak Linux

Linux in the detection of memory leaks (a) the most simple way 专家

What is a memory leak is a memory leak is a dynamic application of the memory in the use of the end of the release, resulting in this memory can not be used to recover the operating system. This procedure, for example, has applied for 4 bytes of space but does not release, there are 4 bytes of memory leaks. #include Namespace STD int; main using () () { *p int = int new (1); <<*p<<endl cout; Return 0...

Memory leak Linux

Java encoding specification expert

Naming conventions for naming conventions The first letter of each word in the class requires capital letters, such as UserService, userService, userservice, and the wrong name. Test cases at the end of the Test, such as UserServiceTest If the abbreviations abbreviations should be at the beginning, all capital letters, such as HTMLEditor error writing. The class name should be used English letters or numbers, there should not be a special character Interface does not start with I Method naming specifications The first letter of the first word, the first letter of the other words From the side...

Java Naming conventions notes

Hibernate5 learning to understand database level concurrency expert

In this paper, the author: resuscitating meters along the address: when we talk about isolation, we always assume that two objects directly either isolated or non isolated; but in fact they do not so obvious boundaries. When we say the transaction of a database, complete isolation requires a high cost. You can't stop the world from getting data in a multi user online transaction processing system. Therefore, there are a lot of isolation level can be used for us to choose. Of course, some of these options are weak in isolation, but can improve the performance and scalability of the system. Transaction isolation level 1.2.3. transaction isolation problem first, we look at a few...

Leetcode notes: Sum Query Range - Immutable expert

Given an array of nums, and j to find the elements between the and I, where the assumption that the I must be less than or equal to `j`, and the array of nums is generally the same. ...

Leetcode C++ Range Sum algorithm

Java memory management and then explore expert

Previously wrote JVM and memory management articles, it now appears that the Java virtual machine and its memory management approach is not enough depth. Today, the combination of books to do a finishing. Source "garbage collection" mechanism is easy to understand. Java language in the creation of the object back to take up memory, as a kind of self protection, to avoid memory leaks, Java provides garbage collection mechanism to recycle the memory space occupied by the object is no longer used. Memory allocation mode on the Java commonly used virtual machine memory allocation, please refer to the previous blog: click here Java virtual machine will be assigned to the object or the number of...

Java JVM memory management

Java basis: SocketChannel and Selector application in ZooKeeper expert

Reprint please indicate the source: jiq - Chin's technical blog if you do not understand the socketchannel and selector, please read my other blog: zookeeper start from the main functions of QuorumPeerMain: calling sequence is: Main - > initializeAndRu...

Leetcode note: Two Integers Divide expert

The meaning of the title is simple and clear, that is not to use the multiplication, division and take more than mod, input two integers, the results of the output division operation. ...

Leetcode C++ Divide Bit operation algorithm

Actual combat string in the c++ series - sixteen decimal string to sixteen decimal integer (usually the color code used) expert

For a long time not to write about the string blog. Because it's almost written. But recently with the string to deal with, so the hormone brain, tadpoles restless. In the process, if you use the color code, the general is the sixteen hex, that is, hex. But the server returns a color string to you, that is, string hex how do you turn this string hex to hex, and use it in your code? Further, what do you do with a hex like "#ffceed" string to RGB? The first question in Jav...


C++11 new characteristics of the application - introduced several new convenient algorithm (used for sorting a few algorithms) expert

Continue to C++11 in the header file algorithm to increase the algorithm. At least I think, in the STL algorithm, the most used is the sort, we do not explore the sort source code, is to introduce a few new C++11 on the sort of function. For a sequence, how do we know that he is not ordered it? This is used: is_sorted Prototype: template Is_sorted_until ForwardIterator (...


Java-18.2 basic understanding of the basic mechanism of the thread (8) multi thread exception capture expert

In this chapter, we'll discuss the abnormal capture of multiple threads. 1 abnormal com.ray.ch17 package; Class Test public { Static void main public (args String[]) { {try ThreadA.Run () new (); {catch} (E Exception) { System.out.println ("catch the difference"...


Java array is divided into sub arrays expert

There is such a requirement, the loop array output dynamic form for a row of two columns Each of the two separate arrays is a group, if the last one is a group Java.util.ArrayList import; Java.util.List import; Class SplitArray public { Static void main public (args String[]) { Ary[] String = {...


LeetCode 225 Stack using Queues Implement (queue to achieve stack) (*) expert

Queue to achieve the operation of the stack as follows. Push (x) - add the element x into the stack Pop () - remove elements from the top of the stack Top () -- the top element of the stack Empty () - the return stack is empty note: you must use a standard operation of the queue. In other words, only push/pop/size/empty and other operations are effective. The queue may not be native support, depending on the language you use. As long as you are using queue standard operation, you can use list or deque (double...

Leetcode Stack Queue Pop Push

C++ development of face gender recognition tutorial (14) - gray image recognition BUG processing expert

In this blog, we're dealing with a very deep BUG in the current program, which causes the program to present some of the logical errors (though not shown in the BUG). A, trigger bug 1, ready to trigger samples to replicate the hidden bug, the need to achieve two test sample preparation, a is color (three channel map) map, and a is a grayscale (single channel): temporary read the two images to verify its properties: that this program is able to properly read the two pictures, will not collapse. 2, modify the code, to trigger BUG analysis to our repair...

MFC Gender identification Opencv

LeetCode 232 Queue using Stacks Implement (using the stack to achieve the queue) (*) expert

Translation stack to achieve the following operation of the queue. Push (x) -- the element X is written to the tail of the queue Pop () - removes the element from the queue header Peek () - returns the queue header element Empty () - to return to the queue is empty note: you must use a standard operation of the stack. In other words, only push/pop/size/empty and other operations are effective. Stack may not be native support, depending on the language you use. As long as you are using stack standard operation, you can use list or dequ...

Pop Leetcode Stack queue Push

Bzoj3252 strategy

Greedy +DFS sequence + segment tree...

Bzoj greedy DFS order Line segment tree

Set Matrix Zeroes LeetCode

If there is a 0 in the matrix, then the row and column of the 0 is set to 0. Required to complete the operation on the given matrix. ...

LeetCode algorithm Python matrix Matrix

RabbitMQ and Java, Spring combined with examples to explain in detail expert

This article describes the rabbitMq, and to RabbitMQ and Java, Spring combination of two examples to demonstrate how to use the RabbitMQ. Also provided how to install RabbitMQ services under Ubuntu. ...

RabbitMQ Spring Java

Edit Distance LeetCode

The minimum edit distance between two strings, namely the original string at least after the operation how many times can become the target string operations, including delete a character, insert a character, a character updates. ...

LeetCode Python algorithm dynamic programming Edit distance

JavaSE entry learning 5:Java basic grammar (1)

One key Keywords overview: Java language has some special purpose word called a keyword. Key word to the Java compiler has a special significance, in the process Order in the application must be careful. Key features: all lowercase letters. Keyword. Key note: goto and const as reserved words, do not use the. 50 commonly used keywords Java (48 plus a reserved word when the word back English it)...

JavaSE Java The DOS command prompt Java syntax Java data type conversion

Generic expert

There is no generic generic before the following two questions: l from aggregation (Collection) to remove an element, we must convert the elements for specific type. L insert elements, the compiler does not check the type of object types you insert and focus elements are the same. Generic role is to tell the compiler that you hope the aggregation of elements is what type, so that the compiler can at compile time to help you check you to insert the element type of the collection is correct; or a gathering remove elements from the elements do not need to cast, because the compiler already know the element type of the gathering. Generic definition...

Type Generic upper bound The lower bound

A style of Java single mode expert

Wrote a lot of singleton, today posted a Book written. A singleton pattern definition: a design pattern that uses only one instance of the class to create an instance. Requirements: there is only one way to create an instance, and it is not a reference to an object that is not initialized. Therefore, in one case, there is a need to declare a construction method for the private, and it is only called once. Package OOP; / * * * single case mode * * lunatictwo @author * / Class public...


11525 - Permutation (two points + tree array)

Title Link: click on open link If you find the n array from all array 1~k, n given by the formula. Thinking: can be found, this formula is Cantor expansion formula (Cantor on Wikipedia: Click to open the link). Then s[i] means that the number of I in the current number of rows in the first few. So, you can use two + tree array fast solution, and a BC topic in spirit. See code for details: #include #include #include #include #include #includ...

UVA ACM-ICPC data structure Tree array Two points