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最新推荐文章于 2022-06-20 23:31:12 发布

原创最新推荐文章于 2022-06-20 23:31:12 发布 · 515 阅读

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#struct #ini #c

//枚举了所有点到目的这条线的所有交点
#include<stdio.h>
#define N 35
struct POINT
{
	double x,y;       
}purpose,a[4];
struct LINE
{
	POINT a, b;  
}line[N];

double chaji(POINT pi,POINT pj,POINT pk)   //叉积
{
	return (pi.x-pk.x)*(pj.y-pk.y)-(pi.y-pk.y)*(pj.x-pk.x);
}
bool cross(POINT a,POINT b,POINT c,POINT d)
{
	if(chaji(a,b,c)*chaji(a,b,d)<0 && chaji(c,d,a)*chaji(c,d,b)<0)
		return 1;
	return 0;
}

int main()
{
	int n,i,j,max,count;
    while(scanf("%d",&n)!=EOF)
    {
        for(i=0;i<n;i++)
			scanf("%lf%lf%lf%lf",&line[i].a.x,&line[i].a.y,&line[i].b.x,&line[i].b.y);
        scanf("%lf%lf",&purpose.x,&purpose.y);
			
        line[i++].a.x=0;line[i].a.y=0;line[i].b.x=100;line[i].b.y=0;
        line[i++].a.x=100;line[i].a.y=0;line[i].b.x=100;line[i].b.y=100;
		line[i++].a.x=100;line[i].a.y=100; line[i].b.x=0;line[i].b.y=100;
		line[i++].a.x=0;line[i].a.y=100;line[i].b.x=0;line[i].b.y=0;
           

        max=9999999;
        for(i=0;i<n+4;i++)
        {
			count=0;
			for(j=0;j<n+4;j++)
				if(cross(line[i].a,purpose,line[j].a,line[j].b))//xiang jiao
					count++;
			if(count<max)
					max=count;
			count=0;
			for(j=0;j<n+4;j++)
				if(cross(line[i].b,purpose,line[j].a,line[j].b))//xiang jiao
					count++;
				if(count<max)
					max=count;
		}
		

		printf("Number of doors = %d\n",max+1);
		
    }
    
	return 0;
}