关于队列的几个小算法

package algorithm;

import java.util.EmptyStackException;
/**
 * 用静态数组实现队列的基本操作
 * 用3个元素记录
 * 实现数组的循环利用
 * @author hasee
 *
 */
public class Queue1 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Queue q = new Queue(3);
		q.offer(1);
		System.out.println(q.peek());
	}
	static class Queue {
		int [] arr ;
		int start,end,size;
		public Queue(int i) {
			if(i<0)
				throw new IllegalArgumentException("the length of Quene is smaller than 0");
			arr = new int[i];
			start = 0;
			end = 0;
			size = 0;
		}
		
		
		//入队
		public void offer(int i)  {
			if(size == arr.length) {
				throw new IndexOutOfBoundsException("the queue id full");
			}
			arr[end] = i;
			end = end==arr.length-1?0:end++;	
			size++;
		}
		//出队
		public  int pop() {
			if(size==0) {
				throw new EmptyStackException();
			}
			int temp = start;
			start = start == arr.length-1?0:start++;
			size--;
			return arr[temp];
		}
		//返回第一个值
		public  int peek() {
			if(size==0) {
				throw new EmptyStackException();
			}
			return arr[start];
		}
	}

}

package algorithm;

import java.util.Stack;

/**
 * 用栈实现队列
 * @author hasee
 *
 */
public class Queue2 {
	
	public static void main(String[] args) {
		Queue q = new Queue();
		q.add(1);
		q.add(2);
		q.add(3);
		q.add(4);
		System.out.println(q.peek());
		System.out.println(q.peek());
	}
	
	static class Queue {
		private Stack<Integer> data = new Stack<Integer>();
		private Stack<Integer> help = new Stack<Integer>();
		
		//加入新元素
		public void add(int i) {
			// TODO Auto-generated method stub
			data.push(i);
		}
		
		//出队列
		public int remove() {
			if(data.size()==0)
				throw new NullPointerException("the queue is null");
			int size1 = data.size();
			for(int i = 0;i < size1;i++) {
				help.push(data.pop());
			}
			int result = help.pop();
			int size2 = help.size();
			for(int j = 0;j < size2;j++)
				data.push(help.pop());
			return result;
		}
		
		//返回队列第一个元素 但不删除
		public int peek() {
			if(data.size()==0)
				throw new NullPointerException("the queue is null");
			while(data.size()>0) {
				help.push(data.pop());
			}
			int result = help.peek();
			while(help.size()>0){
				data.push(help.pop());
			}
			return result;
		}
		
		
	}
}