计算几何 —— 模板

#include<complex>#define sqr(x) ((x)*(x))#define LL long long#define INF 0x3f3f3f3fconst double PI = acos(-1.0);const double eps = 1e-8;#define maxm 210010#define maxn 110using namespace std;struct Point{    double x,y;    Point(double x = 0, double y = 0) : x(x),y(y){}};typedef  Point Vector;Vector operator + (Point A, Point B)  {return  Vector(A.x + B.x,A.y+B.y);}Vector operator - (Point A, Point B)  {return  Vector(A.x - B.x,A.y-B.y);}Vector operator * (Vector A, double p){return  Vector(A.x*p,A.y*p);}double Dot(Vector A, Vector B)   {return A.x * B.x + A.y * B.y;}double Cross(Vector A, Vector B) {return A.x *B.y - A.y*B.x;}double Length(Vector A) {return sqrt(Dot(A,A));}double Angle(Vector A, Vector B) {return acos(Dot(A,B) / Length(A)/Length(B));}//线段struct Segment{    Point a,b;}S[maxn];//复数表示//double Dot(Vector A, Vector B)  {return  real(conj(A)*B);}//double Cross(Vector A,Vector B) {return imag(conj(A)*B);}//double Rotate(Vector A, Vector B) {return A*exp(Point(0,read));}//判断点是否重合bool check(Point A, Point B){    double d = sqrt((A.x-B.x)*(A.x-B.x) + (A.y - B.y)*(A.y-B.y));    if(d < eps)  return true;    else return false;}//直线交点Point GetlineIntersection(Point P, Vector v, Point Q, Vector w){    Vector u = P - Q;    double t  = Cross(w,u)/Cross(v,w);    return P + v*t;}//判断三点是否共线bool judge(Point A, Point B, Point C){    Vector p = A - B;    Vector q = C - B;    if(abs(Cross(p,q)) < eps)        return true;}