I don't know why I keep getting wrong answer... works fine with all the data I tried....
double gx, gy, dx, dy;
while(5 == scanf("%d %lf %lf %lf %lf", &n, &gx, &gy, &dx, &dy))
int i, j, s = 0;
for(i = 0 ; i < n ; i++)
double x, y, dg, dd;
scanf("%lf %lf", &x, &y);
dg = hypot(gx-x, gy-y);
dd = hypot(dx-x, dy-y);
if(dg*2.0 < dd)
printf("The gopher can escape through the hole at (%.3f,%.3f).\n", x, y);
s = 1;
if(!s) printf("The gopher cannot escape.\n");
While we are on the topic, does anyone have any tips for finding "tricky" input ?