NC37 合并区间（C++）- 中等、排序、数组

题目链接：https://www.nowcoder.com/practice/69f4e5b7ad284a478777cb2a17fb5e6a?tpId=196&rp=1&ru=%2Fexam%2Foj&qru=%2Fexam%2Foj&sourceUrl=%2Fexam%2Foj%3Fpage%3D2%26tab%3D%25E7%25AE%2597%25E6%25B3%2595%25E7%25AF%2587%26topicId%3D196&difficulty=&judgeStatus=&tags=&title=37&gioEnter=menu
题目如下：

class Solution {
public:
    static bool cmp(Interval &a,Interval &b){
        if(a.start==b.start) return a.end merge(vector &intervals) {
        vector res;
        if(intervals.size()==0) return res;
        else if(intervals.size()==1) {res.push_back(intervals[0]);return res;}
        sort(intervals.begin(),intervals.end(),cmp);//类型不同。要用cmp
        
        Interval temp;
        int l=intervals[0].start,r=intervals[0].end;
        for(int i=1;i
            if(r>=intervals[i].start){//需要合并
                r=max(r,intervals[i].end);
                
                //temp.start=l;temp.end=r;
                //res.push_back(temp);
                //上面两行不对，因为此时不确定后面一个区间是否要和当前这个区间合并
            }else {//先保存独立的区间，再更新左右指针
                temp.start=l;temp.end=r;
                res.push_back(temp); 
                
                l=intervals[i].start;
                r=intervals[i].end;      
            }
        }
        
        temp.start=l;temp.end=r;
        res.push_back(temp);
        
        return res;
    }
};