题解 | #数据流中的中位数#

public class Solution {
    // 大顶堆   存储数据的左半部分
      PriorityQueue<Integer> leftMaxQueue = new PriorityQueue<Integer>((a,b)->b-a);
      // 小顶堆 存储数据的右半部分
    PriorityQueue<Integer>  rightMinQueue = new PriorityQueue<Integer>((a,b)->a-b);

    public void Insert(Integer num) {
        int len1 = leftMaxQueue.size();
        int len2 = rightMinQueue.size();
        if (len1 == len2){
            if (rightMinQueue.isEmpty()|| num<=rightMinQueue.peek()){
                leftMaxQueue.add(num);
            }else {
                leftMaxQueue.add(rightMinQueue.poll());
                rightMinQueue.add(num);
            }
        }else {
             // 其实 奇数
            if (leftMaxQueue.peek()<=num){
                rightMinQueue.add(num);
                
            }else {
                rightMinQueue.add(leftMaxQueue.poll());
                leftMaxQueue.add(num);
            }
            
        }

    }

    public Double GetMedian() {
        int len1 = leftMaxQueue.size();
        int len2 = rightMinQueue.size();
        if (len1 == len2){
            double left = leftMaxQueue.peek();
            double right = rightMinQueue.peek();
            double mid = (left + right)*0.5;
            return  mid;
        }else {
            double lVal = (double)leftMaxQueue.peek();
            return  lVal;
        }
        
    }
}