UVa 11178 Morley's Theorem(几何)

题目链接：UVa 11178 Morley's Theorem

几何。

完全是按照白书上写的，模版总结的真好。

#include <iostream>
#include <cmath>
#include <cstdio>

struct Point
{
	double x, y;
	Point(double x=0, double y=0):x(x),y(y) { }
};

typedef Point Vector;

Vector operator + (const Vector& A, const Vector& B) { return Vector(A.x+B.x, A.y+B.y); }
Vector operator - (const Point& A, const Point& B) { return Vector(A.x-B.x, A.y-B.y); }
Vector operator * (const Vector& A, double p) { return Vector(A.x*p, A.y*p); }
double Dot(const Vector& A, const Vector& B) { return A.x*B.x + A.y*B.y; }
double Length(const Vector& A) { return sqrt(Dot(A, A)); }
double Angle(const Vector& A, const Vector& B) { return acos(Dot(A, B) / Length(A) / Length(B)); }
double Cross(const Vector& A, const Vector& B) { return A.x*B.y - A.y*B.x; }

Point GetLineIntersection(const Point& P, const Point& v, const Point& Q, const Point& w)
{
	Vector u = P-Q;
	double t = Cross(w, u) / Cross(v, w);
	return P+v*t;
}

Vector Rotate(const Vector& A, double rad)
{
	return Vector(A.x*cos(rad)-A.y*sin(rad), A.x*sin(rad)+A.y*cos(rad));
}

Point read_point()
{
	double x, y;
	scanf("%lf%lf", &x, &y);
	return Point(x,y);
}

Point getD(Point A, Point B, Point C)
{
	Vector v1 = C-B;
	double a1 = Angle(A-B, v1);
	v1 = Rotate(v1, a1/3);

	Vector v2 = B-C;
	double a2 = Angle(A-C, v2);
	v2 = Rotate(v2, -a2/3);

	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 0;
}