计算几何-Dot-Vector

This article is made by Jason-Cow.
Welcome to reprint.
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看了书，然后码

 struct D{
   db x,y;
   D(db x=0.0,db y=0.0):x(x),y(y){}
 };
 typedef D V;
 bl op<(D A,D B){return A.x<B.x||(A.x==B.x&&A.y<B.y);}
 V op+(V A,V B){return V(A.x+B.x,A.y+B.y);}
 V op-(V A,V B){return V(A.x-B.x,A.y-B.y);}
 V op*(V A,db N){return V(A.x*N,A.y*N);}
 V op/(V A,db N){return V(A.x/N,A.y/N);}

int main(){
   A[]=V(,);
   cout<<A[].x<<" "<<A[].y<<endl;
   cout<<A[].x<<" "<<A[].y<<endl;
   A[].y+=1.0,cout<<"add"<<endl;
   A[]=A[]+A[];
   cout<<A[].x<<" "<<A[].y<<endl<<endl;
   sort(A+,A++);
   for(int i=;i<=;i++)cout<<A[i].x<<" "<<A[i].y<<endl;
   return ;
}

add