Leetcode 452. 用最少数量的箭引爆气球

class Solution {
public:
    int findMinArrowShots(vector<pair<int, int>>& points) {
        if(points.size()==0)
            return 0;
        
        sort(points.begin(), points.end(), [](const auto a, const auto b){
                                                                            return a.first < b.first;
                                                                         });
        int short_num = 1;
        int short_beg = points[0].first;
        int short_end = points[0].second;
        for(int i=1; i<points.size(); ++i)
        {
            if(points[i].first <= short_end)
            {
                short_beg = points[i].first;
                if(short_end > points[i].second)
                    short_end = points[i].second;
            }
            else
            {
                ++short_num;
                short_beg = points[i].first;
                short_end = points[i].second;
            }
        }
        return short_num;
    }
};