C 默认大顶堆，java默认小顶堆
代码语言：javascript复制import java.util.Comparator;
import java.util.Iterator;
import java.util.PriorityQueue;
import java.util.Queue;
public class PriorityQueueTest
{
public static class student
{
private String name;
private int stu_num;
public student(String name, int stu_num)
{
this.name = name;
this.stu_num = stu_num;
}
public int getNum()
{
return stu_num;
}
public String getName()
{
return name;
}
public String toString()
{
return getName() " " getNum();
}
}
public static void main(String[] args)
{
/*PriorityQueue(int initialCapacity, Comparator<? super E> comparator)
使用指定的初始容量创建一个 PriorityQueue，并根据指定的比较器对元素进行排序。*/
/*PriorityQueue(int initialCapacity)
使用指定的初始容量创建一个 PriorityQueue，并根据其自然顺序对元素进行排序。*/
//优先级队列遍历不一定有序，但一个一个出队一定有序
Comparator<student> order = new Comparator<student>()
{
public int compare(student s1, student s2)
{
return s1.getNum() - s2.getNum();
}//这里不像C 有greater和less升序降序直接弄，得自己写
};//按学号升序排列
Queue<student> queue = new PriorityQueue<student>(11, order);
queue.add(new student("lcy", 15170040));
queue.add(new student("zj", 15170041));
queue.add(new student("db", 15170039));
queue.add(new student("xcy", 15170020));
queue.add(new student("33y", 15170023));
queue.add(new student("dcy", 15170088));
queue.add(new student("hy", 15170025));
queue.add(new student("sf", 15170031));
while (!queue.isEmpty())
{
System.out.println(queue.poll());
}
System.out.println("====================");
Comparator<Integer> order1 = new Comparator<Integer>()
{
public int compare(Integer o1, Integer o2)
{
return o1 - o2;
}
};//小顶堆，若o2-o1就是大顶堆，迭代器不一定有序，但是顺序出队一定有序
Queue<Integer> q = new PriorityQueue<Integer>(11, order1);
q.add(2);
q.add(1);
q.add(34);
q.add(6);
q.add(9);
q.add(15);
q.add(9);
q.add(11);
q.add(46);
q.add(5);
/*int len = q.size();
for (int i = 0; i < len; i)
{
System.out.print(q.poll() " ");
}
System.out.println(q.toString());*/
Iterator<Integer> it1 = q.iterator();
while (it1.hasNext())
{
System.out.print(it1.next() " ");
}
}
}
