做算法题：合并间隔。答案中有个it->start，我没查到迭代器中有start的操作，是伪代码还是我真的没找到，
想想最可能是作者自己定义操作，那么要如何实现呢，求解答。
#include<iostream>
#include<vector>
using namespace std;
void insert(vector<vector<int> > &intervals,vector<int> newInterval);
vector<vector<int> > merge(vector<vector<int> > intervals)
{
    vector<vector<int> > result;
    for(int i=0;i<intervals.size();i++)
        insert(result,intervals[i]);
    return result;
}
void insert(vector<vector<int> > &intervals,vector<int> newInterval)
{
    vector<vector<int> >::iterator it =intervals.begin();
    while(it!=intervals.end())
    {
        if(newInterval.end()<it->start)
        {
            intervals.insert(it,newInterval);
            return ;
        }
        else if(newInterval.start> it->end)
        {
            it++;
            continue;
        }
        else
        {
            newInterval.start=min(newInterval.start,it->start);
            newInterval.end=max(newInterval.end,it->end);
            it=intervals.erase(it);
        }
    }
    intervals.insert(intervals.end(),newInterval);
}
int main()
{
    int a[][2]={{1,3},{6,7},{8,11},{7,10}};
    vector<vector<int> > aa;
    aa.resize(sizeof(a)/sizeof(a[0]));
    for(int i=0;i<aa.size();i++)
        aa[i].resize(2);
    for(int i=0;i<sizeof(a)/sizeof(a[0]);i++)
    {
        aa[i][0]=a[i][0];
        aa[i][1]=a[i][1];
    }
    vector<vector<int> > result=merge(aa);
    for(int i=0;i<result.size();i++)
    {

        cout<<"{"<<result[i][0]<<","<<result[i][1]<<"}"<<" ";
    }
    cout<<endl;
    return 0;
}

谢谢，原来是leetcode上的题。恍然大悟~