［半平面交］ HDOJ 5462 Manors

#include 
using namespace std;
typedef long long LL;

const int maxn = 1005;
const double eps = 1e-7;

struct Point
{
	double x, y;
	Point(double x = 0, double y = 0) : x(x), y(y) { }
	bool operator  0;
}
Point GetIntersection(Line a, Line b)
{
	Vector u = a.P - b.P;
	double t = Cross(b.v, u) / Cross(a.v, b.v);
	return a.P + a.v * t;
}
int ConvexHull(Point *p, int n, Point *ch)
{
	sort(p, p+n);
	int m = 0;
	for(int i = 0; i  1 && Cross(ch[m-1] - ch[m-2], p[i] - ch[m-2]) = 0; i--) {
		while(m > k && Cross(ch[m-1] - ch[m-2], p[i] - ch[m-2])  1) m--;
	return m;
}
Point p[maxn];
Line q[maxn];
int HalfplaneInersection(Line* L, int n, Point* poly)
{
	sort(L, L+n);
	int first, last;
	q[first = last = 0] = L[0];
	for(int i = 1; i  fabs(b)) P = Point(-c / a, 0);
			else P = Point(0, -c / b);
			line[cnt++] = Line(P, v);
		}
		for(int j = 0; j