452. 用最少数量的箭引爆气球

解法：贪心算法

class Solution {
public:
    static bool cmp(vector<int>x ,vector<int>y){
        return x[1] < y[1];
    }

    int findMinArrowShots(vector<vector<int>>& points) {
        if(points.empty())  return 0;
        sort(points.begin(),points.end(),cmp);	//按尾结点从小到大排序
        int end=points[0][1];
        int res=1;
        for(int i=0;i<points.size();i++){
            if(points[i][0]>end){
                res++;
                end=points[i][1];
            }               
        }
        return res;
    }
};