[leetcode]Merge Intervals

问题描述：

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].

基本思路：

对左边界进行排序，然后对有边界的情况进行分类处理。

代码：

/** * Definition for an interval. * struct Interval { *     int start; *     int end; *     Interval() : start(0), end(0) {} *     Interval(int s, int e) : start(s), end(e) {} * }; */ #include <algorithm>  bool myfunction (Interval A,Interval B)        //C++     {          return (A.start < B.start);     }class Solution {public:        vector<Interval> merge(vector<Interval> &intervals) {        vector<Interval> result;        if(intervals.size() == 0)            return result;        sort(intervals.begin(),intervals.end(),myfunction);                       bool haveStart = false;        int start ;        int end ;        for(int i = 0; i < intervals.size(); i++)        {            if(haveStart == false && i < intervals.size())            {                start = intervals[i].start;                end   = intervals[i].end;                haveStart = true;                continue;            }            if(intervals[i].start <= end )            {                if(intervals[i].end > end)                    end = intervals[i].end;                            }            else             {                Interval tmp(start,end);                result.push_back(tmp);                start = intervals[i].start;                end = intervals[i].end;                            }        }        if(haveStart)        {            Interval tmp(start,end);            result.push_back(tmp);        }        return result;    }};