UVA11178 Morley's Theorem(基础模板)

题目链接

题意：给出A，B, C点坐标求D,E,F坐标，其中每个角都被均等分成三份  

求出 ABC的角a, 由 BC 逆时针旋转 a/3 得到BD,然后 求出 ACB 的角a2, 然后 由 BC顺时针 旋转 a2 / 3得到 DC,然后就交点

 #include <iostream>
 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #include <cmath>
 using namespace std;
 struct Point
 {
     double x, y;
 };
 typedef Point Vector;
 Vector operator + (Vector A, Vector B)
 {
     Vector C;
     C.x = A.x + B.x;
     C.y = A.y + B.y;
     return C;
 }
 Vector operator - (Vector A, Vector B)
 {
     Vector C;
     C.x = A.x - B.x;
     C.y = A.y - B.y;
     return C;
 }
 Vector operator *(Vector A, double b)
 {
     Vector C;
     C.x = A.x * b;
     C.y = A.y * b;
     return C;
 }
 Point read_point()
 {
     Point temp;
     scanf("%lf%lf", &temp.x, &temp.y);
     return temp;
 }
 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)
 {
     Vector C;
     C.x = A.x * cos(rad) - A.y * sin(rad);
     C.y = A.x * sin(rad) + A.y * cos(rad);
     return C;
 }
 double Cross(Vector A, Vector B)
 {
     return A.x * B.y - A.y * B.x;
 }
 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;
 }
 Point getD(Point A, Point B, Point C)
 {
     Vector v1 = C - B;
     double a1 = Angle(A - B, v1);
     v1 = Rotate(v1, a1 / );

     Vector v2 = B - C;
     double a2 = Angle(A - C, v2);
     v2 = Rotate(v2, -a2 / );

     return GetLineIntersection(B, v1, C, v2);

 }
 int main()
 {
     int T;
     Point A, B, C, D, E, F;
     scanf("%d", &T);
     while (T--)
     {
         A = read_point();
         B = read_point();
         C = read_point();
         D = getD(A, B, C);
         E = getD(B, C, A);
         F = getD(C, A, B);

         printf("%.6lf %.6lf %.6lf %.6lf %.6lf %.6lf\n", D.x, D.y, E.x, E.y, F.x, F.y);

     }
     return ;
 }