poj 1089 Intervals

#include<iostream>            //水题
#include<algorithm>
using namespace std;
int n;
struct Node
{
    int beg,end;
    bool operator<(const Node& other)
    {
        if(beg==other.beg)
            return end>other.end;
        return beg<other.beg;
    }
}node[50005];
int main()
{
    cin>>n;
    for(int i=0;i<n;++i)
        cin>>node[i].beg>>node[i].end;
    sort(node,node+n);
    int a=node[0].beg,b=node[0].end;
    for(int i=1;i<n;++i)
    {
        if(node[i].beg==a||node[i].end<=b)
            continue;
        if(node[i].beg<=b)
            b=node[i].end;
        else
        {
            cout<<a<<" "<<b<<endl;
            a=node[i].beg;b=node[i].end;
        }
    }
    cout<<a<<" "<<b<<endl;
    return 0;
}