Merge Intervals 多区间合并

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]​​.

Hide Tags

​​Array​​​ ​​Sort​​

Hide Similar Problems

​​(H) Insert Interval​​

/**
 * Definition for an interval.
 * struct Interval {
 *     int start;
 *     int end;
 *     Interval() : start(0), end(0) {}
 *     Interval(int s, int e) : start(s), end(e) {}
 * };
 */
 
 //比较函数一定要放到类的外面
 bool cmp(const Interval &a,const Interval &b)
    {
        if(a.start==b.start)
            return a.end < b.end;
        return a.start < b.start;
    }
    
class Solution {
public:

    vector<Interval> merge(vector<Interval>& intervals) {
        
        vector<Interval> res;
        
        if(intervals.size()<1)
            return res;
            
        sort(intervals.begin(),intervals.end(),cmp);//排序
        
        for(int i=0;i<intervals.size();i++)
        {
            int left=intervals[i].start;
            int right=intervals[i].end;//保存第一个区间
            
            int j=++i;
            while(j<intervals.size())
            {
                if(intervals[j].start<=right)//如果该区间的start，小于right，说明与前面的重合
                {
                    if(intervals[j].end>right)///如果该区间的end大，更新right
                        right=intervals[j].end;
                    j++;
                }
                else
                    break;
            }
            i=--j;
            Interval ss=Interval(left,right);
            res.push_back(ss);
        }
        return res;
    }
};