参考别人的代码:

import java.util.PriorityQueue;

public class Solution {

    PriorityQueue<Integer> min=new PriorityQueue<>();
    PriorityQueue<Integer> max=new PriorityQueue<>((a,b)->b-a);

    public void Insert(Integer num) {
        max.add(num);
        min.add(max.remove());
        if (min.size()>max.size())
            max.add(min.remove());
    }

    public Double GetMedian() {
        if (min.size() == max.size()){
            return (max.peek()+min.peek())/2.0;
        } else{
            return(double)max.peek();
        }
    }

}