修改dot函数

Author: zhitaogpt

computationGeometry/planeGeometry.cpp

@@ -10,7 +10,7 @@ Vector operator * (Vector A,double a){return Vector(a*A.x,a*A.y);}
 Vector operator / (Vector A,double p){return A*(1/p);}
 bool operator < (const Point  A,const Point  B){return mp(A.x,A.y) < mp(B.x,B.y);}
 bool operator == (const Point A,const Point  B){return !dcmp(A.x-B.x) && !dcmp(A.y-B.y);}
-double Dot(Vector A, Vector B){return A.x*B.x-A.y*B.y;}
+double Dot(Vector A, Vector B){return A.x*B.x+A.y*B.y;}
 double Length(Vector & A){return sqrt(Dot(A,A));}
 double Angle(Vector &A,Vector & B){return acos(Dot(A,B)/Length(A)/Length(B));}
 Vector Rotate(Vector &A,double rad){return Vector(A.x*cos(rad)-sin(rad)*A.y,A.x*sin(rad)+A.y*cos(rad));}

computationGeometry/二维几何.md

@@ -17,7 +17,7 @@ Vector operator * (Vector A,double a){return Vector(a*A.x,a*A.y);}
 Vector operator / (Vector A,double p){return A*(1/p);}
 bool operator < (const Point  A,const Point  B){return mp(A.x,A.y) < mp(B.x,B.y);}
 bool operator == (const Point A,const Point  B){return !dcmp(A.x-B.x) && !dcmp(A.y-B.y);}
-double Dot(Vector A, Vector B){return A.x*B.x-A.y*B.y;}
+double Dot(Vector A, Vector B){return A.x*B.x+A.y*B.y;}
 double Length(Vector & A){return sqrt(Dot(A,A));}
 double Angle(Vector &A,Vector & B){return acos(Dot(A,B)/Length(A)/Length(B));}
 Vector Rotate(Vector &A,double rad){return Vector(A.x*cos(rad)-sin(rad)*A.y,A.x*sin(rad)+A.y*cos(rad));}