1 package com.ys.datastructure;
 2  
 3 public class MyQueue {
 4     private Object[] queArray;
 5     //队列总大小
 6     private int maxSize;
 7     //前端
 8     private int front;
 9     //后端
10     private int rear;
11     //队列中元素的实际数目
12     private int nItems;
13      
14     public MyQueue(int s){
15         maxSize = s;
16         queArray = new Object[maxSize];
17         front = 0;
18         rear = -1;
19         nItems = 0;
20     }
21      
22     //队列中新增数据
23     public void insert(int value){
24         if(isFull()){
25             System.out.println("队列已满！！！");
26         }else{
27             //如果队列尾部指向顶了，那么循环回来，执行队列的第一个元素
28             if(rear == maxSize -1){
29                 rear = -1;
30             }
31             //队尾指针加1，然后在队尾指针处插入新的数据
32             queArray[++rear] = value;
33             nItems++;
34         }
35     }
36      
37     //移除数据
38     public Object remove(){
39         Object removeValue = null ;
40         if(!isEmpty()){
41             removeValue = queArray[front];
42             queArray[front] = null;
43             front++;
44             if(front == maxSize){
45                 front = 0;
46             }
47             nItems--;
48             return removeValue;
49         }
50         return removeValue;
51     }
52      
53     //查看对头数据
54     public Object peekFront(){
55         return queArray[front];
56     }
57      
58      
59     //判断队列是否满了
60     public boolean isFull(){
61         return (nItems == maxSize);
62     }
63      
64     //判断队列是否为空
65     public boolean isEmpty(){
66         return (nItems ==0);
67     }
68      
69     //返回队列的大小
70     public int getSize(){
71         return nItems;
72     }
73      
74 }
75 //测试类
76 package com.ys.test;
77  
78 import com.ys.datastructure.MyQueue;
79  
80 public class MyQueueTest {
81     public static void main(String[] args) {
82         MyQueue queue = new MyQueue(3);
83         queue.insert(1);
84         queue.insert(2);
85         queue.insert(3);//queArray数组数据为[1,2,3]
86          
87         System.out.println(queue.peekFront()); //1
88         queue.remove();//queArray数组数据为[null,2,3]
89         System.out.println(queue.peekFront()); //2
90          
91         queue.insert(4);//queArray数组数据为[4,2,3]
92         queue.insert(5);//队列已满,queArray数组数据为[4,2,3]
93     }
94  
95 }

 1 package com.ys.datastructure;
 2  
 3 public class PriorityQue {
 4     private int maxSize;
 5     private int[] priQueArray;
 6     private int nItems;
 7      
 8     public PriorityQue(int s){
 9         maxSize = s;
10         priQueArray = new int[maxSize];
11         nItems = 0;
12     }
13      
14     //插入数据
15     public void insert(int value){
16         int j;
17         if(nItems == 0){
18             priQueArray[nItems++] = value;
19         }else{
20             j = nItems -1;
21             //选择的排序方法是插入排序，按照从大到小的顺序排列，越小的越在队列的顶端
22             while(j >=0 && value > priQueArray[j]){
23                 priQueArray[j+1] = priQueArray[j];
24                 j--;
25             }
26             priQueArray[j+1] = value;
27             nItems++;
28         }
29     }
30      
31     //移除数据,由于是按照大小排序的，所以移除数据我们指针向下移动
32     //被移除的地方由于是int类型的，不能设置为null，这里的做法是设置为 -1
33     public int remove(){
34         int k = nItems -1;
35         int value = priQueArray[k];
36         priQueArray[k] = -1;//-1表示这个位置的数据被移除了
37         nItems--;
38         return value;
39     }
40      
41     //查看优先级最高的元素
42     public int peekMin(){
43         return priQueArray[nItems-1];
44     }
45      
46     //判断是否为空
47     public boolean isEmpty(){
48         return (nItems == 0);
49     }
50      
51     //判断是否满了
52     public boolean isFull(){
53         return (nItems == maxSize);
54     }
55  
56 }