注：用了一把系统的优先级队列，但是必须自定义比较器
package lesson01;

import java.util.Comparator;
import java.util.PriorityQueue;

public class Code01_PriorityQueue {
  public static void main(String[] args) {
    PriorityQueue<Student> min_heap = new PriorityQueue<>(new IdAscendingComparator() );
    
    Student s1 = new Student("x", 1001);
    Student s2 = new Student("y", 1002);
    Student s3 = new Student("z", 1003);
    
    min_heap.add(s3);
    min_heap.add(s1);
    min_heap.add(s2);
    
    while(! min_heap.isEmpty()) {
      Student student = min_heap.poll();
      System.out.println("Student [name=" + student.name + ", id=" + student.id + "]");
    }
  }
}

class IdAscendingComparator implements Comparator<Student>{

  // 自定义升序
  public int compare(Student o1, Student o2) {
    return o1.id - o2.id;
  }
  
}

class Student{
  String name;
  int id;
  
  public Student(String name, int id) {
    this.name = name;
    this.id = id;
  }
  
}