java 6th edition

Introduction to Java from getting started to giving up: object-oriented concepts (Entry edition ), To know what object orientation is, you must first have an object · Okay, we are joking. We need to explain what object orientation is. Example: "Silly, what did you eat for breakfast today ?" Silly: "You can eat a lot of food. There are two slices of bread, a chicken pie, a few dishes and leaves, a little s

the traditional blocking IO, and if it does not block, then it is non-blocking IO. Received the operating system IO model, but also have to mention SELECT/POLL/EPOLL/IOCP, about the four understanding, not much to explain, I have not understood in place.Understandably, after Linux 2.6, the implementation of Java NIO is achieved through Epoll, which can be found through the source code of the JDK. AIO, which is implemented through IOCP on Windows, i

, then all the columns are finished, find a suitable, continue the third Queen, or the first column, the second column ... Until the 8th queen can be placed in a non-conflicting position, we find a correct solution. Then go back to the first queen to put the second column, back to continue the loop ...Okay, start on the code.Package huisu;/** * Created by Wolf on 2016/3/16. */public class Wolfqueen {/** * total number of Queens (at this time set to 8 queens in the 8x8 chessboard, you can modi

. Through the synchronous lock, it realizes the mutually exclusive access to "cruelty". for the production method produce () : When the warehouse is full, the producer thread waits and waits for the consumer to consume the product before the production line can be produced; After the producer thread has finished producing the product, all threads that synchronize the lock are awakened through Notifyall (), including " Consumer thread ", what we call" informing consumers of consumption ". for co

pair. Each time we compare, we copy the larger numbers from the back to the secondary array, making sure the numbers in the auxiliary array are ascending. After copying the larger number to the array, move the corresponding pointer forward one bit, then proceed to the next round of comparisons.After the detailed discussion above, we suspect summed up the process of statistical reverse order: First, the array is separated into sub-arrays, the number of reverse pairs in the sub-array is counted,

Java code to implement:/** * Enter an array of integers with positive and negative numbers in the array. One or more consecutive integers in an array make up a sub-array. * The maximum value of all sub-arrays is evaluated. Requires time complexity O (n) */package swordforoffer;/** * @author Jinshuangqi * * August 8, 2015 */public class E31greatestsumofsubarrays {Pub Lic Integer findgreatestsum (int[] arr) {if (arr.length ==0) return null; int greate

it.Analysis here, we can see that this is actually a very typical recursive thinking, so we write the following Java code:/** * Enter a string to print out all the permutations of the string. * For example, enter the string ABC, print out all the strings that can be arranged by the character A,b,c ABC,ACB,BAC,BCA,CAB,CBA */package swordforoffer;/** * @author Jinshuangqi * * August 7, 2015 */public class E28stringpermutation {public void swap (char[]

pointer is introduced, so we have to deal with the empty list separately. When the first linked list is an empty list, that is, its head node is a null pointer, then it is merged with the second linked list, and the process of the idler merge is the second linked list. Similarly, when the head node of the second linked list is a null pointer, we combine it with the first linked list to get the first linked list. If two linked lists are empty lists, the result of merging is to get an empty list.

numbers are pressed into the stack and the next number is not found, then the sequence cannot be a pop-up sequence.After the formation of clear ideas, we can have some code, the following is the implementation of Java code./** * Enter a sequence of two integers, the first sequence represents the stack's indentation order, and determine if the second sequence is the pop-up order for the stack. */package swordforoffer;import java.util.stack;/** * @auth

people met in the number 2, the benchmark number 3 and this 2 exchange, get a new array 2 1 0 3 7 9 3 5, the 3 as a split point, the entire array is divided into two parts, the left 2 1 0 and the right 7 9 3 Repeat the above steps to continue sortingThe Java code is as follows: Public classQuickSort { Public Static voidMain (string[] args) {//TODO auto-generated Method StubQuickSort QS=NewQuickSort (); int[] score = {10,9,8,7,6,5,4,3,2,1}; Qs.quickso

[] Bubblesortresult =px. Bubblesort (score); for(inti=0;i) {System.out.print (Bubblesortresult[i]+" "); } } /** Bubble sort * @param score score (0-10 points) * @return return count array * Description: There are n number, two adjacent number comparison, if the previous number is smaller than the number of the subsequent exchange position, assuming that a minimum number is placed in the most Back to a trip, you need to compare 1~n-1, set the number of times I, each trip compared to 1~n

complexity O (1) */package swordforoffer;/** * @author Jinshuangqi * * August 10, 2015 */public class E40numbersappearo nce {public void findnumsappearonce (int[] arr) {if (arr = = null) return;int number = 0;for (int i:arr) Number^=i;int index = f INDFIRSTBITIS1 (number), int number1= 0,number2 = 0;for (int i:arr) {if (IsBit1 (I,index)) number1^=i;elsenumber2^=i;} System.out.println (NUMBER1); System.out.println (number2);} private int findFirstBitIs1 (int number) {int indexbit = 0;while ((num

Sword refers to Offer interview question 27 (Java edition): Binary Search Tree and two-way linked list, sword refers to offer Question: enter a binary search tree and convert it into a sorted two-way linked list. It is required that a new node cannot be created. You can only adjust the point of the node pointer in the tree. For example, in the binary search tree, the two-way linked list after the output con

of the list is the 1th node in the bottom. * For example, a list of 6 nodes. Starting from the beginning, their values are sequentially 1. 2. 3,4,5. 6. The 3rd node of the list is the node with a value of 4 */package swordforoffer;import utils. listnode;/** * @author Jinshuangqi * * August 1, 2015 */public class E15kthnodefromend {public ListNode findkthtotail (listnode Head,int k) {if (head = = NULL | | k Test example; function tests (the K-node is in the middle of the list, and the K-node is

down as a dot class can not look at. the Private Doublex; the Private Doubley; - PublicPoint (DoubleXDoubley) { in This. x =x; the This. y =y; the } About PublicPoint () { thex = 0.0; they = 0.0; the } + Public voidSetPoint (DoubleXDoubleY) { - This. x =X; the This. y =Y;Bayi } the Public DoubleGetX () { the returnx; - } - Public DoubleGetY () { the returny; the } the Public Static Dou

The Texas-web3j-solidity project is a Java version that uses the WEB3J package and the ETH network to interact with the applet.The following features are mainly implemented:1. Release of contract2. Initiating a transfer3. Inquire about transactions4. Call the Smart Contract methodThe Texas-web3j-solidity project has made the following functional modifications on the basis of the official examples:1. Add Texas contract for game recharge and withdrawal

OverviewIn distributed systems, there are scenarios that require the use of a globally unique ID, which can be used to prevent ID collisions using a 36-bit UUID, but the UUID has some drawbacks, first he is relatively long, and the UUID is generally unordered.There are times when we want to use a simple ID and want the ID to be generated in an orderly fashion.The snowflake of Twitter solved this demand, and initially Twitter migrated the storage system from MySQL to Cassandra, because Cassandra

:" + getthumbprint (cert));Conn.disconnect ();}private static String Getthumbprint (X509Certificate cert) throws Exception {MessageDigest MD = messagedigest.getinstance ("SHA-1");byte[] der = cert.getencoded ();Md.update (der);Byte[] Digest = Md.digest ();Return Bytestohexstring (Digest);}private static String bytestohexstring (byte[] src) {StringBuilder StringBuilder = new StringBuilder ("");if (src = = NULL | | src.length return null;}for (int i = 0; i int v = src[i] 0xFF;String HV = integer.

Create a class that contains an int field and a char field that are not initialized and print them out to verify that Java performs the default initialization.public class Domtest{int I;char c;public domtest () {System.out.println ("i=" +i+ "\nc=[" +c+ "]" + "\ n []");/** * Print result as follows I =0 c=[] []//only for comparison reference */}/** * @param args */public static void main (string[] args) {new domtest ();}}

E51duplicationinarray {Publ IC Boolean duplicate (int[] arr) {if (arr== null | | arr.length . In the code, although there are one or two repetitions, but each number can be exchanged up to two times to find their own location, so the total time complexity is O (n), in addition, all the operation steps are on the input array, do not need to allocate additional memory, so the space complexity is O (1). Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not