UVA - 10245 The Closest Pair Problem

#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<cmath>
#include<string.h>
const int INF = 0x3f3f3f3f;
const int NINF = -INF -1;
using namespace std;
struct point {
double x, y;
};
point poi[10010];
double dis(point a, point b) {
return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
}
int main() {
int n;
while (scanf("%d", &n) && n != 0) {
for (int i = 0; i < n; i++) {
scanf("%lf%lf", &poi[i].x, &poi[i].y);
}
double minn = INF;
for (int i = 0; i < n; i++)
for (int j = i+1; j < n; j++) {
double tmp = dis(poi[i], poi[j]);
if (tmp < minn) minn = tmp;
}
if (minn > 10000) printf("INFINITY\n");
else printf("%.4lf\n", minn);

}
return 0;
}