54. 数据流中的中位数

class Solution {
        priority_queue<int> maxHeap;//大顶堆维护小于中位数的所有元素
        priority_queue<int, vector<int>, greater<int>> minHeap;//小顶堆维护大于中位数的所有元素。数字越大，优先级越低
public:
    void insert(int num){
        maxHeap.push(num);//每次直接把当前数插入到下一个堆
        /*两个堆的元素数量差不能超过2，超过2就互相匀一匀*/
        if(maxHeap.size() > minHeap.size() + 1)
        {
            int t = maxHeap.top();
            maxHeap.pop();
            minHeap.push(t);
        }
        /*如果大顶堆最大值 大于 小顶堆最小值，则交换*/
        while(minHeap.size() && maxHeap.top() > minHeap.top())//保证大顶堆有元素，同时大顶堆最大值大于小顶堆最小值
        {
            int t1 = maxHeap.top();
            int t2 = minHeap.top();
            maxHeap.pop(); maxHeap.push(t2);
            minHeap.pop(); minHeap.push(t1);
        }
    }

    double getMedian(){
        int n1 = minHeap.size();
        int n2 = maxHeap.size();
        if(n1 == n2) return (minHeap.top() + maxHeap.top()) / 2.0;
        else return maxHeap.top();
    }
};