规范相交模板struct point{double x,y;};double det(double x1,double y1,double x2,double y2){return x1*y2-x2*y1;}double cross(point a,point b,point c){return det(a.x-c.x,a.y-c.y,b.x-c.x,b.y-c.y);}int segcrossSimple(point a,point a,point c,point d){return (dblcmp(cross(a,c,d))^dblcmp(cross(b,c,d))==-2)&&(dblcmp(cross(c,a,b))^dblcmp(cross(d,a,b))==-2);}^按位异或a^b==-2等价于ab<0或者ab==-1;
，看自家总在期待,不知将来好歹,新乐吧总在不断等待,
