leetcode - 56. Merge Intervals

/**
 * 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:
    static bool cmp(Interval a,Interval b)
    {
        if(a.start!=b.start) return a.start<b.start;
        return a.end>b.end;
        
    }
    vector<Interval> merge(vector<Interval>& intervals) {
        vector<Interval> ret;
        if(!intervals.size()) return ret;
        sort(intervals.begin(),intervals.end(),cmp);
        Interval in(intervals[0].start,intervals[0].end);
        for(auto it:intervals)
        {
            if(it.start>in.end)
            {
                ret.push_back(in);
                in=it;
            }else{
                in.end=max(in.end,it.end);
            }
        }
        ret.push_back(in);
        return ret;
    }
};