poj2610

简单题

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
using namespace std;

#define eps 1.0E-8

double xx1,xx2,yy1,yy2;

double dist(double x1, double y1, double x2, double y2)
{
    double x = abs(x1 - x2);
    double y = abs(y1 - y2);
    return sqrt(x * x + y * y);
}

bool ok(double x, double y)
{
    double d1 = dist(xx1, yy1, x, y);
    double d2 = dist(xx2, yy2, x, y);
    if (d1 * 2 + eps < d2)
        return true;
    return false;
}

int main()
{
    //freopen("t.txt", "r", stdin);
    scanf("%lf%lf%lf%lf", &xx1, &yy1, &xx2, &yy2);
    double x, y;
    while (scanf("%lf%lf", &x, &y) != EOF)
    {
        if (ok(x, y))
        {
            printf("The gopher can escape through the hole at (%.3f,%.3f).\n", x, y);
            return 0;
        }
    }
    printf("The gopher cannot escape.\n");
    return 0;
}