zoj1041 Transmitters

/* *********************************************** Author :xryz Email :[email protected] Created Time :4-4 10:03:00 File Name :Transmitters.cpp ************************************************ */

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <math.h>
#include <stdlib.h>
#include <time.h>
using namespace std;

bool dis(double x1,double y1,double x0,double y0,double r)
{
    double sum=(x1-x0)*(x1-x0)+(y1-y0)*(y1-y0);
    if(sum>r) return 0;
    return 1;
}

bool fnc(double x1,double y1,double x2,double y2)
{
    double t=x1*y2-x2*y1;
    if(t<=0) return 1;
    return 0;
}
int main()
{
    double x0,y0,r,x[160],y[160],in[160];
    int sum,ans,i,n,j;
    while(~scanf("%lf %lf %lf",&x0,&y0,&r))
    {
        if(r<0) break;
        r=r*r;
        ans=0;
        memset(in,0,sizeof(in));
        scanf("%d",&n);
        for(i=0;i<n;i++)
        {
            scanf("%lf%lf",&x[i],&y[i]);
            in[i]=dis(x[i],y[i],x0,y0,r);
        }
        sum=0；
        for(i=0;i<n;i++)
        {
            if(in[i])
            {
                sum=0;
                for(j=0;j<n;j++)
                {
                    //if(i==j) continue;
                    if(in[j])
                    {
                        if(fnc(x[i]-x0,y[i]-y0,x[j]-x0,y[j]-y0))
                            sum++;
                    }
                }
                if(sum>ans) ans=sum;
            }
        }
        printf("%d\n",ans);
    }
    return 0;
}