凸包判交板子

#define int long long
int sgn(double x) {
    if(fabs(x) < eps)return 0;
    if(x < 0)return -1;
    else return 1;
}

struct Point {
    int x,y;
    Point() {}
    Point(int _x,int _y) {
        x = _x;
        y = _y;
    }
    Point operator -(const Point &b)const {
        return Point(x - b.x,y - b.y);
    }
    int operator ^(const Point &b)const {
        return x*b.y - y*b.x;
    }
    int operator *(const Point &b)const {
        return x*b.x + y*b.y;
    }
    friend int dis2(Point a) {
        return a.x*a.x+a.y*a.y;
    }
    friend bool operator<(const Point &a,const Point &b){
        if(fabs(a.y-b.y)<eps) return a.x<b.x;
        return a.y<b.y;
    }
};
typedef Point Vector;
double Dot(Point A, Point B){return A.x*B.x+A.y*B.y;}//点积
double Cross(Vector A,Vector B){return A.x*B.y-A.y*B.x;}//叉积
double Length(Vector A){return sqrt(Dot(A,A));}//OA长
double Angle(Point A,Point B){return acos(Dot(A,B)/Length(A)/Length(B));}//OA和OB的夹角
//判断线段相交,不在端点相交
bool SegmentProperIntersection(Point a1,Point a2,Point b1,Point b2){
    double c1=Cross(a2-a1,b1-a1),c2=Cross(a2-a1,b2-a1),c3=Cross(b2-b1,a1-b1),c4=Cross(b2-b1,a2-b1);
    return sgn(c1)*sgn(c2)<eps&&sgn(c3)*sgn(c4)<eps;
}

int graham(Point p[],int n,Point q[]){
     int top=1;
     sort(p,p+n);
     if(n==0) return 0;
     q[0]=p[0];
     if(n==1) return 1;
     q[1]=p[1];
     if(n==2) return 2;
     q[2]=p[2];
     for(int i=2;i<n;i++){
         while(top&&(Cross(q[top]-q[top-1],p[i]-q[top-1])<=0)) top--;
         q[++top]=p[i];
     }
     int len=top;
     q[++top]=p[n-2];
     for(int i=n-3;i>=0;i--){
         while(top!=len&&(Cross(q[top]-q[top-1],p[i]-q[top-1])<=0)) top--;
         q[++top]=p[i];
     }
     return top;
}

bool C_S(Point *ch1,int t1,Point *ch2,int t2)//判断凸包是否相交
{
    double angle[1010],x;
    int i,j,k,m;
    if(t1==1)return true;
    if(t1==2)
    {
        for(i=0;i<t2;i++)
        {
            k=sgn(Cross(ch1[1]-ch1[0],ch2[i]-ch1[0]));
            if(k==0&&Dot(ch1[1]-ch1[0],ch2[i]-ch1[0])>0)
            {
                if(Length(ch2[i]-ch1[0])<Length(ch1[1]-ch1[0]))break;
            }
        }
        if(i<t2)return false;
        if(t2==2&&SegmentProperIntersection(ch1[0],ch1[1],ch2[0],ch2[1]))return false;
        return true;
    }
    angle[0]=0;
    for(i=2;i<t1;i++)
    angle[i-1]=Angle(ch1[1]-ch1[0],ch1[i]-ch1[0]);
    for(i=0;i<t2;i++)
    {
        j=sgn(Cross(ch1[1]-ch1[0],ch2[i]-ch1[0]));
        if(j<0||(j==0&&Dot(ch1[1]-ch1[0],ch2[i]-ch1[0])<0))continue;
        j=sgn(Cross(ch1[t1-1]-ch1[0],ch2[i]-ch1[0]));
        if(j>0||(j==0&&Dot(ch1[t1-1]-ch1[0],ch2[i]-ch1[0])<0))continue;
        x=Angle(ch1[1]-ch1[0],ch2[i]-ch1[0]);
        m=lower_bound(angle,angle+t1-1,x)-angle;
        if(m==0)j=0;
        else j=m-1;
        k=sgn(Cross(ch1[j+1]-ch2[i],ch1[j+2]-ch2[i]));
        if(k>=0)break;
    }
    if(i<t2)return false;
    return true;
}