POJ 2610

#include<iostream>
#include<iomanip>
using namespace std;

int main()
{
    //freopen("acm.acm","r",stdin);
    double x1;
    double y1;
    double x2;
    double y2;
    double hol_x;
    double hol_y;
    double len_gop;
    double len_dog;
    bool boo = false;
    cin>>x1>>y1>>x2>>y2;
    while(cin>>hol_x>>hol_y)
    {
        len_gop = (x1-hol_x)*(x1-hol_x) + (y1-hol_y)*(y1-hol_y);
        len_dog = (x2-hol_x)*(x2-hol_x) + (y2-hol_y)*(y2-hol_y);
        if(len_dog/4.000 > len_gop)
        {
            cout<<"The gopher can escape through the hole at ("<<setiosflags(ios::fixed)<<setprecision(3)<<hol_x<<","<<hol_y<<")."<<endl;
            boo = true;
            break;
        }
    }
    if(!boo)
        cout<<"The gopher cannot escape."<<endl;
}