数据结构队列的java实现，包括线性和链式两种方式

实现的思路为：

采用泛型的方式，首先定义了一个Queue的接口，然后通过实现该接口实现了线性和链式的两种形式的队列：

接口代码如下：

 package com.peter.java.dsa.interfaces;

 public interface Queue<T> {

     /* put item at rear of queue; */
     void insert(T data);

     /* take item from front of queue */
     T remove();

     /* peek at front of queue */
     T peek();

     boolean isEmpty();

     boolean isFull();

     int size();

     void clear();
 }

线性栈的代码如下：

 package com.peter.java.dsa.common;

 import com.peter.java.dsa.interfaces.Queue;

 public class LinearQueue<T> implements Queue<T> {
     private int capacity;
     private T[] t;
     private int front;
     private int rear;
     private int size;

     public LinearQueue() {
         // TODO Auto-generated constructor stub
         capacity = 16;
         t = (T[]) new Object[capacity];
         front = -1;
         rear = -1;
         size = 0;
     }

     public LinearQueue(int capacity) {
         this.capacity = capacity;
         t = (T[]) new Object[capacity];
         front = -1;
         rear = -1;
         size = 0;
     }

     @Override
     public void insert(T data) {
         // TODO Auto-generated method stub
         if (isEmpty()) {
             front = (front + 1) % t.length;
             t[front] = data;
             rear = (rear + 1) % t.length;
         } else {
             if (isFull()) {
                 resize();
             }
             rear = (rear + 1) % t.length;
             t[rear] = data;
         }
         size++;
     }

     @Override
     public T remove() {
         // TODO Auto-generated method stub
         T tmp = null;
         if (!isEmpty()) {
             tmp = t[front];
             t[front] = null;
             front = (front + 1) % t.length;
             size--;
         }
         return tmp;
     }

     @Override
     public T peek() {
         // TODO Auto-generated method stub
         T tmp = null;
         if (!isEmpty()) {
             tmp = t[front];
         }
         return tmp;
     }

     @Override
     public boolean isEmpty() {
         // TODO Auto-generated method stub
         return front + rear == -2 && front == rear % t.length;
     }

     @Override
     public boolean isFull() {
         // TODO Auto-generated method stub
         return front == rear % t.length;
     }

     @Override
     public int size() {
         // TODO Auto-generated method stub
         return size;
     }

     @Override
     public String toString() {
         // TODO Auto-generated method stub
         StringBuffer buffer = new StringBuffer();
         buffer.append("Linear Queue Content:[");
         if (front < rear) {
             for (int i = front; i < rear + 1; i++) {
                 buffer.append(t[i] + ",");
             }
         } else {
             for (int i = front; i < t.length; i++) {
                 buffer.append(t[i] + ",");
             }
             for (int i = 0; i < rear + 1; i++) {
                 buffer.append(t[i] + ",");
             }
         }
         buffer.append("]");
         buffer.replace(buffer.lastIndexOf(","), buffer.lastIndexOf(",") + 1, "");
         return buffer.toString();
     }

     private void resize() {
         int oldSize = t.length;
         T[] tmp = (T[]) new Object[oldSize * 2];
         for (int i = 0; i < oldSize; i++) {
             tmp[i] = t[front];
             front = (front + 1) % oldSize;
         }
         front = 0;
         rear = oldSize - 1;
     }

     @Override
     public void clear() {
         // TODO Auto-generated method stub
         front = -1;
         rear = -1;
     }

 }

随着复习进度，后续代码会陆续更新。