java practice exam

java.math.*;p ublic class main{public static void Main (string[] args) { Scanner in= new Scanner (system.in); int A; String test; A=in.nextint (); Biginteger[] num= new biginteger[210]; Num[1]=biginteger.one; Num[2]=biginteger.valueof (2); Num[3]=biginteger.valueof (3); while (a-->0) { test=in.next (); int n=test.length (); if (nHDU 2100 binary conversion, the method may be cumbersome but also pro

Today to more than a large number of Java brush, to fight for the easy water after the large number of problems ~HDU 1002 Large number Add Link: http://acm.hdu.edu.cn/showproblem.php?pid=1002CodeImport Java.util.*;import Java.math.biginteger;public class main{public static void Main (string[] args) { Scanner in=new Scanner (system.in); int N=in.nextint (); for (int i=1;iHDU 1042 Large number of factorial links: http://acm.hdu.e

strictly follow the use of volatile conditions-that is, the variable is really independent of the other variables and its own previous values-in some cases you can use the volatile substitution synchronized to simplify the code. However, volatile the code used is often more error-prone than code that uses locks. The pattern described in this article covers some of the most common use cases that can be used volatile instead synchronized . Following these patterns (not exceeding their limits when

Package Com.text_1;public class Cat { //write Java applications as required. (1) Create a class named Cat://Properties: Name, fur color, age//behavior: Display name, Yell//(2) Write main class://Create an object cat, named "Nicole", Hair color is "gray", age is 2 years old, the screen to lose//out of the object's hair color and age, Let the object call the display name and shout two methods. String Name,color;int age;cat (string name,strin

Package Com.text_1;public class Student {//write Java applications. First, define the class--student that describe the student, including attributes such as study number (int),//Name (String), age (int), and two methods: Student (int stuno,string name,int)//For initializing an object, Output () is used for outputting student information. Next, define a main class--//testclass, create multiple objects of the student class in the main method, use these

the method that specifies the file that the Formtemplateid points to3 */4 PublicString Downloadformtemplatebyid ()throwsexception{5HttpServletRequest request=servletactioncontext.getrequest ();6HttpServletResponse response=servletactioncontext.getresponse ();7String formtemplateid=request.getparameter ("Formtemplateid");8Formtemplate formtemplate=Formtemplateservice.getformtemplatebyid (Formtemplateid);9File file=NewFile (Formtemplate.geturl ());TenString Filename=urlencoder.encode (F

Java Theory and Practice: Correct Use of Volatile variables (1) The volatile variable in Java can be seen as a "to a lesser extent"synchronized"; AndsynchronizedCompared with the block, the volatile variable requires less encoding and less runtime overhead. However, the only function it can implement issynchronized. This article introduces several effective mod

This is my note on the Java course of learning web. The original video link is: http://www.imooc.com/learn/855-1 Basic NotationSelf-complementary shortcut keys: ALT +/5-2 input and outputUse the Scanner tool class to get user-entered score informationThe scanner class is located in the Java.util package and needs to be imported when using the packagesteps:1. Import Java.util.Scanner2. Create a Scanner object3. Receive and save user-entered valuesdiffe

1. The string is not the first of 8 basic data types, string is an object.Because the default value of the object is NULL, the default value of string is also null, but it is a special object that has some features that other objects do not have.2. New string () and new String ("") are all declarations of a new empty string, that is, the empty string is not null;3. String str= "Kvill";String Str=new string ("Kvill"), the difference:Here, we don't talk about heaps, or stacks, simply introduce the

return 0; the}G. Flood problemsTime limit: C/s 1 sec, other languages 2 secondsSpace limitations: C/C + + 32768K, other languages 65536K64bit IO Format:%lldLinks: Https://www.nowcoder.com/acm/contest/75/GSource: Cow Network topic Description Give a number n, ask 1 to N, how many number is not a multiple of 2 5 11 13. Input Description:There are multiple sets of inputsOne number per line n,1Output Description:The output output of each row is not a multiple of 2 5 11 13.Example 1 input15Outpu

(); } PublicItem Next () {if(!hasnext ())Throw Newnosuchelementexception (); Item Item=Current.item; Current=Current.next; returnitem; } } //Check internal invariants Private BooleanCheck () {//check a few properties of instance variable ' first ' if(N ) { return false; } if(n = = 0) { if(First! =NULL)return false; } Else if(n = = 1) { if(First = =NULL)return false; if(First.next! =NULL)return false; } Else {

table obtains some not the rule law: is not the law of Law:ON the cusp, you can change the condition. Let the condition change with the outer loop. With a pointed face, you can initialize the value so that the initialization changes with the outer loop. 4, Print diamond (◇) or pyramid/* ----* ---* * --* * * -* * * * * * * * * * * * * * -* * * * --* * * ---* * ----* */ Copy Code code as follows: Class ForForTest2 { public static void Main (string[] args) { for (int x=0;

, removes the last element from the container in the method body and joins the consumer. Examples of use are: carcontainerIf you have another setThe method Pop (setOur idea is that the pop receives the parameter application is "E of some kind of superclass set", through the "and Super keyword combined use just can achieve this purpose, namely setThird edition public void pop (setAfter the modification, setWith the use of the extends or Super keyword on the method parameters, you get th

different serialversionuid and possibly the same. To improve the independence and certainty of serialversionuid, it is strongly recommended that the definition serialversionuid be displayed in a serializable class, giving it a definite value. There are two ways to explicitly define SERIALVERSIONUID:1) In some cases, you want the different versions of the class to be serializable compatible, so you need to ensure that the different versions of the class have the same serialversionuid;2) In some

relationship. What about using the map collection? When there is a mapping between the data, you need to think of the map collection first. Idea: 1, converts a string into a character array. Because you want to operate on every single letter. 2, define a map collection, because the letters of the printed results are in order, so use the TreeMap collection. 3. Iterate through the character array. Use each letter as a key to check the map collection. If NULL is returned, the letter and 1 are stor

Volatile variables in the Java language can be thought of as "light", and synchronized synchronized volatile variables require less coding and run-time overhead than blocks, but only part of the functionality that they can implement synchronized . This article describes several patterns for using volatile variables effectively, and highlights several scenarios where volatile variables are not appropriate. The lock provides two main features: Mutual ex

Write multi-threaded applications that simulate multiple people through a cave:1, this cave can only pass one person each time, each person passes through the cave for 5 seconds 2, randomly generated 10 people, at the same time to prepare the cave, showing the name of each person through the cave Muthreadtest.java Packagecom. Train; Public classmuthreadtest{ Public Static voidMain (string[] args) {//TODO auto-generated Method Stub//Create a caveTunnel Tul =NewTunnel (); //10 people across the

-based method or temporal table method, you should first look for a set-based solution to solve the problem, and the set-based approach is generally more efficient.22. Try to avoid large transaction operation and improve the system concurrency ability.23. Try to avoid the return of large data to the client, if the amount of data is too large, should consider whether the corresponding demand is reasonable.By doing Itoo from V1.0 To V3.0, plus the previous project, in fact, when doing SQL optimiza

1220Conversion of arbitrary binary numbers (2-62) to each otherThe method is converted into 10 and then converted into the desired system by taking the remainder method.CodeImport Java.util.*;import java.math.*;p ublic class main{public static void Main (string[] args) {Scanner in=new Scanner ( system.in); int n=in.nextint (); while (n-->0) {int a,b;a=in.nextint (); B=in.nextint (); String Str=in.next (); BigInteger big=biginteger.zero;int k=0;for (int i=str.length () -1;i>=0;i--) {if (Str.char

How to construct the parent and child classes:If there is a default parameterless constructor in the parent class, calls are made automatically in the constructor of the child class. If the parent class has its own constructor, and the parent does not have a default parameterless constructor, then in the constructor of the subclass, you must call a constructor of the parent class, and it must be called in the first statement of the constructed method, in the form super () If placed in another pl