循環(huán)隊(duì)列相關(guān)背景###

什么是隊(duì)列就不解釋了
頭尾相接的順序存儲(chǔ)結(jié)構(gòu)稱(chēng)為循環(huán)隊(duì)列（circular queue）。

循環(huán)隊(duì)列中需要注意的幾個(gè)重要問(wèn)題：

①隊(duì)空的判定條件，隊(duì)空的條件是front=rear；

②隊(duì)滿(mǎn)的判定條件，（rear+1）%QueueSize=front。QueueSize為隊(duì)列初始空間大小。

import com.sun.corba.se.impl.orbutil.graph.Node;
import com.sun.corba.se.spi.presentation.rmi.IDLNameTranslator;

/**
 * Created by junyi.pc on 2017/1/25.
 */

public class Main {
    public  int array[];
    public int size;
    public  int front;
    public int rear;


public Main(int size){
    array =new int[size];
    this.size=size;
    front=0;
    rear=0;
}
 public void enqueue(int value){

     if((rear+1)%size==front){
         //隊(duì)列滿(mǎn)了
         throw new  ArrayIndexOutOfBoundsException();
     }
     else{
         array[rear]=value;
         rear=(rear+1)%size;
     }
 }
    public int dequeue(){
        if(rear==front) {
            //說(shuō)明滿(mǎn)了
            return 0;
        }
            else{
                int temp=front;
                front=(front+1)%size;
                return array[temp];
            }
        }


    public boolean isEmpty() {
        return size == 0;
    }
   public int getLength(){
       if(rear>front){
           return  rear-front;
       }
       else {
           return array.length-1;
       }
   }

    public static void main(String[] args){
      Main  queue=new Main(5);
        queue.enqueue(1);
        queue.enqueue(2);
        queue.enqueue(3);

        System.out.println(queue.dequeue());
        System.out.println(queue.dequeue());
        System.out.println(queue.dequeue());
    }
}

運(yùn)行結(jié)果

C:\java\jdk1.8.0_25\bin\java -Didea.launcher.port=7534 "-Didea.launcher.bin.path=C:\Program Files (x86)\JetBrains\IntelliJ IDEA Community Edition 2016.1\bin" -Dfile.encoding=UTF-8 -classpath "C:\java\jdk1.8.0_25\jre\lib\charsets.jar;C:\java\jdk1.8.0_25\jre\lib\deploy.jar;C:\java\jdk1.8.0_25\jre\lib\ext\access-bridge-64.jar;C:\java\jdk1.8.0_25\jre\lib\ext\cldrdata.jar;C:\java\jdk1.8.0_25\jre\lib\ext\dnsns.jar;C:\java\jdk1.8.0_25\jre\lib\ext\jaccess.jar;C:\java\jdk1.8.0_25\jre\lib\ext\jfxrt.jar;C:\java\jdk1.8.0_25\jre\lib\ext\localedata.jar;C:\java\jdk1.8.0_25\jre\lib\ext\nashorn.jar;C:\java\jdk1.8.0_25\jre\lib\ext\sunec.jar;C:\java\jdk1.8.0_25\jre\lib\ext\sunjce_provider.jar;C:\java\jdk1.8.0_25\jre\lib\ext\sunmscapi.jar;C:\java\jdk1.8.0_25\jre\lib\ext\sunpkcs11.jar;C:\java\jdk1.8.0_25\jre\lib\ext\zipfs.jar;C:\java\jdk1.8.0_25\jre\lib\javaws.jar;C:\java\jdk1.8.0_25\jre\lib\jce.jar;C:\java\jdk1.8.0_25\jre\lib\jfr.jar;C:\java\jdk1.8.0_25\jre\lib\jfxswt.jar;C:\java\jdk1.8.0_25\jre\lib\jsse.jar;C:\java\jdk1.8.0_25\jre\lib\management-agent.jar;C:\java\jdk1.8.0_25\jre\lib\plugin.jar;C:\java\jdk1.8.0_25\jre\lib\resources.jar;C:\java\jdk1.8.0_25\jre\lib\rt.jar;C:\Users\junyi.pc\Desktop\client\out\production\client;C:\Program Files (x86)\JetBrains\IntelliJ IDEA Community Edition 2016.1\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain Main
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Process finished with exit code 0