leetcode + 不断增加数据，求中位数+二分

https://leetcode.com/problems/find-median-from-data-stream/description/

class MedianFinder {
public:
    vector<int> nums;
    /** initialize your data structure here. */
    MedianFinder() {
        
    }
    void addNum(int num) {
        int left = 0, right = nums.size()-1;
        while (left<=right) {
            int mid = (left+right)/2;
            if(nums[mid] < num) left = mid+1;
            else right = mid-1;
        }
        nums.insert(nums.begin()+left, num);
    }
    
    double findMedian() {
        int n = nums.size();
        if(n%2==1) return nums[n/2];
        return (nums[n/2-1]+nums[n/2])/2.0;
    }
};


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