Leetcode Find Median from Data Stream

题意：找出一列数组中的中位数。

思路：使用multiset，并维护一个指针，指向中位数，根据新加入的数的大小来向左向右移动指针。

class MedianFinder {public:    /** initialize your data structure here. */    MedianFinder() {        mid = INT_MIN;        cout = 0;        it = s.begin();    }        void addNum(int num) {        s.insert(num);        cout ++;        if((double)num >= mid || (double)num >= *it) {            if(cout % 2 == 0) {                tempit = it;                tempit ++;                mid = (*it + *tempit) / 2;            }            else {                it ++;                mid = *it;            }        }        else {            if(cout % 2 == 0) {                tempit = it;                it --;                mid = (*it + *tempit) / 2;            }            else {                mid = *it;            }        }                return;    }        double findMedian() {        return mid;    }    private:    double mid;    int cout;    std::multiset<double> s;    std::multiset<double>::iterator it;    std::multiset<double>::iterator tempit;};/** * Your MedianFinder object will be instantiated and called as such: * MedianFinder obj = new MedianFinder(); * obj.addNum(num); * double param_2 = obj.findMedian(); */

另一种思路是维护两个优先队列，一个大于中位数，一个小于中位数。