Java数据结构和算法--栈与队列

（1)栈 

 package ChapterOne;

 public class Stack {
     //栈数组
     long stackArr[];
     //栈的大小
     int maxSize;
     //栈的顶部
     int top;
     //初始化一个大小为size的栈
     public Stack(int size){
         maxSize = size;
         stackArr = new long[size];
         top = -1;
     }
     //出栈操作
     public long pop(){
         return stackArr[top--];
     }
     //进栈操作
     public void push(long value){
         stackArr[++top] = value;
     }
     //判断栈是否为空
     public boolean isEmpty(){
         return top == -1;
     }
     //判断栈是否已满
     public boolean isFull(){
         return top == maxSize-1;
     }
     //取栈顶元素
     public long peek(){
         return stackArr[top];
     }
     public static void main(String[] args) {
         Stack stack = new Stack(10);
         while(!stack.isFull()){
             long v = (long) (Math.random()*100);
             stack.push(v);
             System.out.print(v+" ");
         }
         System.out.println();
         while(!stack.isEmpty()){
             long topValue = stack.pop();
             System.out.print(topValue+" ");
         }
         System.out.println();
     }
 }

(2)队列 

 package ChapterOne;

 public class Queue {
     //队列数组
     private long queueArr[];
     //队列的前端下标
     private int front;
     //队列的尾端下标
     private int rear;
     //队列的大小
     private int maxSize;
     //队列中元素的个数
     private int nItems;
     //初始化一个大小为size的队列
     public Queue(int size){
         queueArr = new long[size];
         maxSize = size;
         front = 0;
         rear = -1;
         nItems = 0;
     }
     //插入操作
     public void insert(long value){
         //队列已满
         if(rear == maxSize-1)
             rear = -1;
         queueArr[++rear] = value;
         nItems++;
     }
     //删除操作
     public long remove(){
         long temp = queueArr[front++];
         if(front == maxSize)
             front = 0;
         nItems--;
         return temp;
     }
     //返回队列第一个元素
     public long peakFront(){
         return queueArr[front];
     }
     //判断是否为空
     public boolean isEmpty(){
         return nItems == 0;
     }
     //判断是否已满
     public boolean isFull(){
         return nItems == maxSize;
     }
     //返回队列中元素的个数
     public int size(){
         return nItems;
     }

     public void print(){
         for(int i = front;i < front+nItems;i++){
             System.out.print(queueArr[i]+" ");
         }
         System.out.println();
     }

     public static void main(String[] args) {
         Queue q = new Queue(10);
         while(!q.isFull()){
             long value = (long)(Math.random()*100);
             q.insert(value);
         }
         q.print();
         while(!q.isEmpty()){
             q.remove();
             q.print();
         }
         q.print();
         System.out.println(q.isEmpty());
     }
 }

(3)优先队列 

 package ChapterOne;

 public class PriorityQueue {

     private int nItems;

     private long pqArr[];

     private int maxSize;

     public PriorityQueue(int size){
         maxSize = size;
         pqArr = new long[size];
         nItems = 0;
     }

     public void insert(long value){
         int i;
         if(nItems == 0)
             pqArr[nItems++] = value;
         else{
             for(i = nItems-1;i >= 0;i--){
                 if(value < pqArr[i]){
                     pqArr[i+1] = pqArr[i];
                 }
                 else
                     break;
             }
             pqArr[i+1] = value;
             nItems++;
         }
     }

     public long remove(){
         return pqArr[--nItems];
     }

     public boolean isEmpty(){
         return nItems == 0;
     }

     public boolean isFull(){
         return nItems == maxSize;
     }

     public void print(){
         for(int i = 0;i < nItems;i++)
             System.out.print(pqArr[i]+" ");
         System.out.println();
     }

     public static void main(String[] args) {
         PriorityQueue pq = new PriorityQueue(10);
         while(!pq.isFull()){
             long value = (long)(Math.random()*100);
             pq.insert(value);
         }
         pq.print();
     }
 }