POJ 2002 Squares

#include <iostream>
#include <cstdio>
#include <cstring>
#include <map>
#include <algorithm>
using namespace std;
map<int,int> mp;
long long cnt;
struct point{
int x;
int y;
};
point p[2000];

bool cmp(point a, point b)
{
if(a.x == b.x) return a.y < b.y;
return a.x < b.x;
}
int main()
{
int i,t1,t2,n,tx,ty,t3,t4,j;
while (1)
{
scanf("%d",&n);
if (n == 0)
break;
cnt=0;
mp.clear();
for (i=0; i<n; i++)
{
scanf("%d%d",&p[i].x,&p[i].y);
mp[p[i].x*100000+p[i].y]=1;
}
sort(p,p+n,cmp);
for (i=0; i<n; i++)
{
for (j=i+1; j<n; j++)
{
t1=p[i].x+p[i].y-p[j].y;
t2=p[i].y-p[i].x+p[j].x;
t1=100000*t1+t2;
t3=p[j].x+p[i].y-p[j].y;
t4=p[j].y-p[i].x+p[j].x;
t3=t3*100000+t4;
if (mp.find(t1) != mp.end() && mp.find(t3) != mp.end())
cnt++;
}
}
printf("%lld\n",cnt/2);
}
}