Leetcode-Merge Intervals

Given a collection of intervals, merge all overlapping intervals.

For example,
Given [1,3],[2,6],[8,10],[15,18],
return [1,6],[8,10],[15,18].

/** * Definition for an interval. * struct Interval { *     int start; *     int end; *     Interval() : start(0), end(0) {} *     Interval(int s, int e) : start(s), end(e) {} * }; */class Solution {public:    vector<Interval> merge(vector<Interval>& intervals) {        if(intervals.empty())            return vector<Interval>{};        vector<Interval> res;        sort(intervals.begin(),intervals.end(),[](Interval a, Interval b){return a.start < b.start;});        res.push_back(intervals[0]);        for(int i=1;i<intervals.size();i++){            if(res.back().end<intervals[i].start)                res.push_back(intervals[i]);            else                res.back().end = max(res.back().end, intervals[i].end);        }        return res;    }};