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java數(shù)組實(shí)現(xiàn)隊(duì)列及環(huán)形隊(duì)列實(shí)現(xiàn)過(guò)程解析

更新時(shí)間：2019年10月09日 09:40:29 作者：小龍_T無(wú)限

這篇文章主要介紹了java數(shù)組實(shí)現(xiàn)隊(duì)列及環(huán)形隊(duì)列實(shí)現(xiàn)過(guò)程解析,文中通過(guò)示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值,需要的朋友可以參考下

代碼內(nèi)容

ArrayQueue---用數(shù)組實(shí)現(xiàn)隊(duì)列

package com.structure;

import java.util.Scanner;

/**
 * @auther:：9527
 * @Description: 數(shù)組模擬隊(duì)列
 * @program: jstl2
 * @create: 2019-10-05 08:58
 */
public class ArrayQueueDemo {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    //測(cè)試
    ArrayQueue queue = new ArrayQueue(3);
    char key = ' '; //接受用戶輸入
    boolean loop = true; //循環(huán)終止判斷器
    while (loop) {
      System.out.println("s(show):顯示隊(duì)列");
      System.out.println("(e(exit)):退出程序");
      System.out.println("a(add):添加數(shù)據(jù)到隊(duì)列");
      System.out.println("g(get):從隊(duì)列取出數(shù)據(jù)");
      System.out.println("h(head):查看隊(duì)列頭部的數(shù)據(jù)");
      System.out.println("按提示輸入......");
      key = scanner.next().charAt(0); //接收數(shù)據(jù)
      switch (key) {
        case 's':
          queue.showQueue();
          break;
        case 'a':
          System.out.println("請(qǐng)輸入一個(gè)數(shù)");
          int value = scanner.nextInt();
          queue.addQueue(value);
          break;
        case 'g':
          try {
            int res = queue.getQueue();
            System.out.printf("取出的數(shù)是%d\n", res);
          } catch (Exception e) {
            System.out.println(e.getMessage());
          }
          break;
        case 'h':
          try {
            int res = queue.headQueue();
            System.out.printf("隊(duì)列頭部的數(shù)是%d\n", res);
          } catch (Exception e) {
            System.out.println(e.getMessage());
          }
          break;
        case 'e':
          scanner.close();
          loop = false;
          break;
        default:
          System.out.println("...輸入不合法，請(qǐng)重新輸入...");
          break;
      }
    }
    System.out.println("程序退出....");
  }
}

//使用數(shù)組模擬隊(duì)列--編寫一個(gè)ArrayQueue
class ArrayQueue {
  private int maxSize; //數(shù)組的最大容量
  private int front; //隊(duì)列頭
  private int rear; //隊(duì)列尾
  private int[] arr; //存放數(shù)據(jù)的數(shù)組，模擬隊(duì)列.

  //創(chuàng)建隊(duì)列的構(gòu)造器
  public ArrayQueue(int arrMaxSize) {
    maxSize = arrMaxSize;
    arr = new int[maxSize];
    front = -1;
    rear = -1;
  }

  //判斷隊(duì)列是否已經(jīng)滿了
  public boolean isFull() {
    return rear == maxSize - 1;
  }

  //判斷隊(duì)列是否為空
  public boolean isEmpty() {
    return rear == front;
  }

  //添加數(shù)據(jù)到隊(duì)列
  public void addQueue(int n) {
    //判斷隊(duì)列是否已滿
    if (isFull()) {
      System.out.println("隊(duì)列已滿，不能添加");
      return;
    }
    rear++; //指針后移
    arr[rear] = n;
  }

  //數(shù)據(jù)出隊(duì)列
  public int getQueue() {
    //判斷隊(duì)列是否為空
    if (isEmpty()) {
      throw new RuntimeException("隊(duì)列為空，不能取數(shù)據(jù)");
    }
    front++; //頭部指針后移
    return arr[front];
  }

  //顯示隊(duì)列的所有數(shù)據(jù)
  public void showQueue() {
    if (isEmpty()) {
      System.out.println("隊(duì)列為空，沒(méi)有數(shù)據(jù)");
      return;
    }
    for (int i = 0; i < arr.length; i++) {
      System.out.printf("arr[%d]=%d\n", i, arr[i]);
    }
  }

  //顯示隊(duì)列的頭部數(shù)據(jù)，這個(gè)不是取出數(shù)據(jù)
  public int headQueue() {
    //判斷是否為空
    if (isEmpty()) {
      System.out.println("隊(duì)列為空，沒(méi)有數(shù)據(jù)....");
      throw new RuntimeException("隊(duì)列為空，沒(méi)有數(shù)據(jù)....");
    }
    return arr[front + 1];
  }
}

改進(jìn)版---環(huán)形隊(duì)列：

環(huán)形隊(duì)列代碼

package com.structure;

import java.util.Scanner;

/**
 * @auther:：9527
 * @Description: 環(huán)形隊(duì)列
 * @program: jstl2
 * @create: 2019-10-05 09:53
 */
public class CircleArrayQueueDemo {
  public static void main(String[] args) {

    //創(chuàng)建一個(gè)環(huán)形隊(duì)列 這里輸入最大數(shù)是4，其實(shí)有效的是3
    CircleArray queue = new CircleArray(4);
    char key = ' '; // 接收用戶輸入
    Scanner scanner = new Scanner(System.in);//
    boolean loop = true;
    // 輸出一個(gè)菜單
    while (loop) {
      System.out.println("s(show): 顯示隊(duì)列");
      System.out.println("e(exit): 退出程序");
      System.out.println("a(add): 添加數(shù)據(jù)到隊(duì)列");
      System.out.println("g(get): 從隊(duì)列取出數(shù)據(jù)");
      System.out.println("h(head): 查看隊(duì)列頭的數(shù)據(jù)");
      key = scanner.next().charAt(0);// 接收一個(gè)字符
      switch (key) {
        case 's':
          queue.showQueue();
          break;
        case 'a':
          System.out.println("輸出一個(gè)數(shù)");
          int value = scanner.nextInt();
          queue.addQueue(value);
          break;
        case 'g': // 取出數(shù)據(jù)
          try {
            int res = queue.getQueue();
            System.out.printf("取出的數(shù)據(jù)是%d\n", res);
          } catch (Exception e) {
            // TODO: handle exception
            System.out.println(e.getMessage());
          }
          break;
        case 'h': // 查看隊(duì)列頭的數(shù)據(jù)
          try {
            int res = queue.headQueue();
            System.out.printf("隊(duì)列頭的數(shù)據(jù)是%d\n", res);
          } catch (Exception e) {
            // TODO: handle exception
            System.out.println(e.getMessage());
          }
          break;
        case 'e': // 退出
          scanner.close();
          loop = false;
          break;
        default:
          break;
      }
    }
    System.out.println("程序退出~~");
  }

}

class CircleArray {
  private int maxSize; //數(shù)組的最大容量
  //front 變量調(diào)整：front就指向隊(duì)列的第一個(gè)元素，即：arr[front]=arr[0]
  private int front;
  //rear 變量調(diào)整：rear 初始值為0 指向隊(duì)列的最后一個(gè)元素的位置，因?yàn)樾枰粘鲆粋€(gè)位置作約束
  private int rear;
  private int[] arr;

  //構(gòu)造器
  public CircleArray(int arrMaxSize) {
    maxSize = arrMaxSize;
    arr = new int[maxSize];
  }

  //判斷隊(duì)列是否已滿
  public boolean isFull() {
    return (rear + 1) % maxSize == front;
  }

  //判斷隊(duì)列是否為空
  public boolean isEmpty() {
    return rear == front;
  }

  //添加數(shù)據(jù)到隊(duì)列
  public void addQueue(int n) {
    //判斷隊(duì)列是否已滿
    if (isFull()) {
      System.out.println("隊(duì)列已滿，不能添加數(shù)據(jù)");
      return;
    }
    //直接加入數(shù)據(jù)
    arr[rear] = n;
    //rear 后移，后移的時(shí)候，要通過(guò)取模來(lái)實(shí)現(xiàn)環(huán)形后移
    rear = (rear + 1) % maxSize;
  }

  //獲取隊(duì)列的數(shù)據(jù)，出隊(duì)列
  public int getQueue() {
    if (isEmpty()) {
      throw new RuntimeException("隊(duì)列為空，不能取數(shù)據(jù)");
    }
    //由于front是指向隊(duì)列的第一個(gè)元素，所以需要
    // 1、front的值先保存到臨時(shí)變量
    //2、將front后移一位，通過(guò)取模實(shí)現(xiàn)環(huán)形后移，
    // 3、將臨時(shí)變量返回
    int temp = arr[front];
    front = (front + 1) % maxSize;
    return temp;
  }

  //顯示隊(duì)列的所有數(shù)據(jù)
  public void showQueue() {
    if (isEmpty()) {
      System.out.println("隊(duì)列為空，沒(méi)有數(shù)據(jù)~");
      return;
    }
    //遍歷環(huán)形隊(duì)列....這里有個(gè)小技巧，需要記住
    for (int i = front; i < front + size(); i++) {
      System.out.printf("arr[%d]=%d\n", i % maxSize, arr[i % maxSize]);
    }
  }

  //求出當(dāng)前隊(duì)列有效數(shù)據(jù)的個(gè)數(shù)
  public int size() {
    return (rear + maxSize - front) % maxSize;
  }

  //顯示隊(duì)列的頭部數(shù)據(jù)
  public int headQueue(){
    //判斷是否為空
    if (isEmpty()){
      throw new RuntimeException("隊(duì)列為空，沒(méi)有數(shù)據(jù)");
    }
    return arr[front];
  }
}

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