m个询问

#include<cstdio>
#include<cstdlib>
#include<cmath>
using namespace std;
int n,m;
double px[15],py[15],qx[15],qy[15];
int dcmp(double a,double b)
{
if (fabs(a-b)<=1e-9) return 0;
if (a<b)return -1;
return 1;
}
double Cross(double x1,double y1,double x2,double y2)
{
return x1*y2-x2*y1;
}
void calc(double x1,double y1,double x0,double y0,double &retx,double &rety)
{
retx=(x0*(x1*x0+y1*y0)+y0*(x0*y1-x1*y0))/(x0*x0+y0*y0);
rety=(y0*(x1*x0+y1*y0)-x0*(x0*y1-x1*y0))/(x0*x0+y0*y0);
}
int dp(double x,double y,int t)
{
if (!t)
{
if (dcmp(x,100.0)<0&&dcmp(x,0.0)>0&&dcmp(y,100.0)<0&&dcmp(y,0.0)>0)
return 1;
return 0;
}
if (dcmp(Cross(x-px[t],y-py[t],qx[t]-px[t],qy[t]-py[t]),0.0)>=0)return 0;
else
{
double retx,rety;
calc(x-px[t],y-py[t],qx[t]-px[t],qy[t]-py[t],retx,rety);
retx+=px[t];rety+=py[t];
return dp(x,y,t-1)+dp(retx,rety,t-1);
}
}
int main()
{
double _x,_y;
scanf("%d",&n);
for (int i=1;i<=n;i++)scanf("%lf%lf%lf%lf",&px[i],&py[i],&qx[i],&qy[i]);
scanf("%d",&m);
while (m--)
{
scanf("%lf%lf",&_x,&_y);
printf("%d\n",dp(_x,_y,n));
}
return 0;
}  

posted on 2018-02-17 16:50  宣毅鸣  阅读(123)  评论(0编辑  收藏  举报