Java中的PriorityQueue

import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.Scanner;
 
public class Main
{
	public static void main(String[] args)
	{
		Scanner in = new Scanner(System.in);
 
		while (in.hasNextInt())
		{
			int n = in.nextInt();
			if (n == 0) break;
 
			PriorityQueue<integer> q1 = new PriorityQueue<integer>(n); // 小数在队列头
			PriorityQueue<integer> q2 = new PriorityQueue<integer>(n, new Comparator<integer>()// 大数在队列头
					{
						public int compare(Integer o1, Integer o2)
						{
							return o2 - o1;
						}
					});
 
			for (int i = 0; i != n; ++i)
			{
				int tmp = in.nextInt();
				q1.offer(tmp);
				q2.offer(tmp);
			}
 
			for (int i = 0; i != n - 1; ++i)
			{
				int a = q1.poll();
				int b = q1.poll();
 
				q1.offer(a * b + 1);
				a = q2.poll();
				b = q2.poll();
				q2.offer(a * b + 1);
			}
 
			System.out.println(q1.peek() - q2.peek());
		}
	}
}