AC一：

#include<iostream>
#include<algorithm>
using namespace std;
int ls[100000], gq[100000];
int main()
{
int i=0;
while((cin>>ls[i]>>gq[i])&&(ls[i]||gq[i]))
{
	 i++;
	while((cin>>ls[i]>>gq[i])&&(ls[i]||gq[i]))
	i++;
    sort(ls,ls+i);
	 sort(gq,gq+i);
	 cout<<ls[0]<<" "<<gq[0]<<" "<<ls[i-1]<<" "<<gq[i-1]<<endl;
	 i=0;

}
return 0;
}

AC二：

#include<iostream>
#include<algorithm>
using namespace std;
struct co
{
	int x;
	int y;
}per[10000];
bool cmp1(co a,co b)
{
	return a.x<b.x;
}
bool cmp2(co a,co b)
{
	return a.y<b.y;
}

int main()
{
	int x,y,i=0;
while(1)
{
	i=0;
while((cin>>per[i].x>>per[i].y)&&(per[i].x||per[i].y))
	{i++;}
     if(!i)
	 {
	
		 break;
	 }
	sort(per,per+i,cmp1);
	int k=per[0].x;int m=per[i-1].x;
	sort(per,per+i,cmp2);
	int l=per[0].y;int u=per[i-1].y;
	cout<<k<<" "<<l<<" "<<m<<" "<<u<<endl;
}
return 0;
}