数据流中的中位数

class Solution {
public:
    void Insert(int num)
    {
        if((count&1) == 0)
        {
            if(max.size()>0 &&num < max.front())
            {
                max.push_back(num);
                push_heap(max.begin(), max.end(), less<int>());
                num = max.front();
                pop_heap(max.begin(), max.end(), less<int>());
                max.pop_back();
            }
            min.push_back(num);
            push_heap(min.begin(), min.end(), greater<int>());
        }
        else
        {
            if(min.size()>0 &&num > min.front())
            {
                min.push_back(num);
                push_heap(min.begin(), min.end(), greater<int>());
                num=min.front();
                pop_heap(min.begin(), min.end(), greater<int>());
                min.pop_back();
            }
            max.push_back(num);
            push_heap(max.begin(), max.end(), less<int>());
             
        }
        ++count;
         
    }
 
    double GetMedian()
    {
        if(count == 0)
            return -1;
        if((count &1) == 0)
            return ((double)max.front() + (double)min.front())/2;
        else return min.front();
    }
private:
    vector<int> max;
    vector<int> min;
    int count = 0;
 
};