双向循环队列的数组实现

需要说明的是此算法我并没有测试过，所以只能用用来参考！

package source;

public class Deque {
	private int maxSize;
	private int left;
	private int right;
	private int nItems;
	private long[] myDeque;
	//constructor
	public Deque(int maxSize){
		this.maxSize = maxSize;
		this.myDeque = new long[this.maxSize];
		this.nItems = 0;
		this.left = this.maxSize;
		this.right = -1;
	}
	//insert a number into left side
	public void insertLeft(long n){
		if(this.left==0) this.left = this.maxSize;
		this.myDeque[--this.left] = n;
		this.nItems++;
	}
	//insert a number into right side
	public void insertRight(long n){
		if(this.right==this.maxSize-1) this.right = -1;
		this.myDeque[++this.right] = n;
		this.nItems++;
	}
	//remove from left
	public long removeLeft(){
		long temp = this.myDeque[this.left++];
		if(this.left==this.maxSize) this.left = 0;
		this.nItems--;
		return temp;
	}
	//remove from right
	public long removeRight(){
		long temp = this.myDeque[this.right--];
		if(this.left==-1) this.left = this.maxSize-1;
		this.nItems--;
		return temp;
	}
	//return true if deQue is empty
	public boolean isEmpty(){
		return (this.nItems==0);
	}
	//return size of the deQue
	public int size(){
		return this.nItems;
	}
}

 双向循环队列的用处很大，可以做为普通队列，也可以用来做栈来用！