Leetcode-295-Find Median from Da

设计数据结构的题目，自由度大难度也大，看了Stefan大神的解法五体投地……果然是思维方式决定解法的简洁程度啊……Stefan大神只用了两个优先队列和一个变号操作就把这问题完美解决了……贴上代码，学习一下：

class MedianFinder {
    priority_queue<long> small, large;
public:

    void addNum(int num) {
        small.push(num);
        large.push(-small.top());
        small.pop();
        if (small.size() < large.size()) {
            small.push(-large.top());
            large.pop();
        }
    }

    double findMedian() {
        return small.size() > large.size()
               ? small.top()
               : (small.top() - large.top()) / 2.0;
    }
};