Find Median from Data Stream_2.cpp

class MedianFinder {
public:
    /** initialize your data structure here. */
    MedianFinder() {
        
    }
    
    void addNum(int num) {
        if(maxPQ.empty() || num <= maxPQ.top())
            maxPQ.push(num);
        else
            minPQ.push(num);
        rebalance();
    }
    
    double findMedian() {
        if(maxPQ.size() > minPQ.size())
            return maxPQ.top();
        else if(maxPQ.size() < minPQ.size())
            return minPQ.top();
        else
            return (maxPQ.top() + minPQ.top()) / 2.0;
    }
    
private:
    priority_queue<int> maxPQ;
    priority_queue<int, vector<int>, greater<int>> minPQ;
    
    void rebalance()
    {
        if(maxPQ.size() > minPQ.size() + 1)
        {
            minPQ.push(maxPQ.top());
            maxPQ.pop();
        }
        else if(minPQ.size() > maxPQ.size() + 1)
        {
            maxPQ.push(minPQ.top());
            minPQ.pop();
        }
    }
};

/**
 * Your MedianFinder object will be instantiated and called as such:
 * MedianFinder obj = new MedianFinder();
 * obj.addNum(num);
 * double param_2 = obj.findMedian();
 */