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].

排序

/**
 * Definition for an interval.
 * struct Interval {
 *     int start;
 *     int end;
 *     Interval() : start(0), end(0) {}
 *     Interval(int s, int e) : start(s), end(e) {}
 * };
 */
struct cmp{
    bool operator()(Interval  a,Interval b){
        return a.start < b.start ;
        
    }  
} comp;
class Solution {
public:
    vector<Interval> merge(vector<Interval> &intervals) {
        sort(intervals.begin(),intervals.end(),comp);
        int size = intervals.size();
        vector<Interval> re;
        if(intervals.size()==0)return re;
        Interval temp;
        int flag = 0;
        for(int i = 0 ; i  < size ;i++)
        {
            if(intervals[i].start >temp.end || flag ==0)
            {
                if(flag ==0)
                {
                    flag =1;
                    temp.start = intervals[i].start;
                    temp.end = intervals[i].end;
                }
                else
                {
                    re.push_back(temp);
                    temp.start =intervals[i].start;
                    temp.end =intervals[i].end;
                }
            }
            else if(intervals[i].start <= temp.end)
            {
                if(temp.end < intervals[i].end)temp.end = intervals[i].end;
            }
        }
        re.push_back(temp);
        return re;
    }
};