内容非常详细,不懂请耐性看完,关键步骤都有注释
队列Queue
普通数组模拟队列
/**
package dataStructure;
import java.util.Scanner;
public class Queue {
public static void main(String[] args) {
ArrayQueue arrayQueue = new ArrayQueue(3);
char key = ' ';
Scanner sc = new Scanner(System.in);
boolean loop = true;
while(loop) {
System.out.println("d(display):显示队列");
System.out.println("a(add):添加数据到队列");
System.out.println("e(exit):退出程序");
System.out.println("g(get):从队列中取出数据");
System.out.println("p(peek):查看队列头数据");
key = sc.next().charAt(0);
switch(key) {
case 'a':
System.out.println("输入一个数");
int e = sc.nextInt();
arrayQueue.addQueue(e);
break;
case 'd':
arrayQueue.display();;
break;
case 'g':
try {
int res = arrayQueue.getQueue();
System.out.printf("取出的数据是%d\n",res);
}catch(Exception E) {
System.out.println(E.getMessage());
}
break;
case 'p':
try {
int res = arrayQueue.peekQueue();
System.out.printf("队列头的数据是%d\n",res);
}catch(Exception E) {
System.out.println(E.getMessage());
}
break;
case 'e':
sc.close();
loop = false;
break;
default:
break;
}
}
System.out.println("程序退出");
}
}
class ArrayQueue{
private int maxSize;
private int front;
private int rear;
private int[] array;
public ArrayQueue(int arrmaxSize){
maxSize = arrmaxSize;
front = -1;
rear = -1;
array = new int[arrmaxSize];
}
public boolean isEmpty() {
return front == rear;
}
public boolean isFull() {
return rear == maxSize - 1;
}
public void addQueue(int e) {
if(isFull()) {
System.out.println("队列已满~~");
return;
}
rear++;
array[rear] = e;
}
public int getQueue() {
if(isEmpty()) {
throw new RuntimeException("队列中没有元素");
}
return array[++front];
}
public void display() {
if(isEmpty()) {
System.out.println("d队列中没有元素");
return;
}
for(int i = 0;i < array.length;i++) {
System.out.printf("array[%d]=%d\n",i,array[i]);
}
}
public int peekQueue() {
if(isEmpty()) {
throw new RuntimeException("队列中没有元素");
}
return array[front + 1];
}
}
数组模拟环形队列
/**
- 思路如下:
- front变量的含义做一个调整: front 就指向队列的第一个元素 也就是说array[front]就是队列的第一个元素front的初始值=0
- rear变量的含义做一个调整: rear指向队列的最后一个元素的后一个位置.因为希望空出一个空间做为约定.rear的初始值=0
3.当队列满时,条件是(rear +1) %maxSize== front [满]
4.对队列为空的条件,rear= front
5.当我们这样分析,队列中有效的数据的个数(rear+ maxSize - front)% maxsize
- */
package dataStructure;
import java.util.Scanner;
public class CircularQueue {
public static void main(String[] args) {
CircularArray arrayQueue = new CircularArray(3);
char key = ' ';
Scanner sc = new Scanner(System.in);
boolean loop = true;
while(loop) {
System.out.println("d(display):显示队列");
System.out.println("a(add):添加数据到队列");
System.out.println("e(exit):退出程序");
System.out.println("g(get):从队列中取出数据");
System.out.println("p(peek):查看队列头数据");
System.out.println("请输入对应功能的字符");
key = sc.next().charAt(0);
switch(key) {
case 'a':
System.out.println("输入一个数");
int e = sc.nextInt();
arrayQueue.addQueue(e);
break;
case 'd':
arrayQueue.display();;
break;
case 'g':
try {
int res = arrayQueue.getQueue();
System.out.printf("取出的数据是%d\n",res);
}catch(Exception E) {
System.out.println(E.getMessage());
}
break;
case 'p':
try {
int res = arrayQueue.peekQueue();
System.out.printf("队列头的数据是%d\n",res);
}catch(Exception E) {
System.out.println(E.getMessage());
}
break;
case 'e':
sc.close();
loop = false;
break;
default:
break;
}
}
System.out.println("程序退出");
}
}
class CircularArray{
private int maxSize;
private int front;
private int rear;
private int[] array;
public CircularArray(int arrmaxSize){
maxSize = arrmaxSize;
array = new int[arrmaxSize];
}
public boolean isEmpty() {
return front == rear;
}
public boolean isFull() {
return (rear+1) % maxSize == front;
}
public void addQueue(int e) {
if(isFull()) {
System.out.println("队列已满~~");
return;
}
array[rear] = e;
rear = (rear+1) % maxSize;
}
public int getQueue() {
if(isEmpty()) {
throw new RuntimeException("队列中没有元素");
}
int value = array[front];
front = (front+1) % maxSize;
return value;
}
public void display() {
if(isEmpty()) {
System.out.println("d队列中没有元素");
return;
}
for(int i = front;i < front + size();i++) {
System.out.printf("array[%d]=%d\n", i % maxSize,array[i%maxSize]);
}
}
public int size() {
return (rear + maxSize - front) % maxSize;
}
public int peekQueue() {
if(isEmpty()) {
throw new RuntimeException("队列中没有元素");
}
return array[front];
}
}
本文内容由网友自发贡献,版权归原作者所有,本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容,请联系:hwhale#tublm.com(使用前将#替换为@)