UVA 11178 Morley's Theorem .

题目地址：https://vjudge.net/problem/UVA-11178

模板题

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <complex>
using namespace std;

/*Point模板部分*/
typedef complex<double> Point;
typedef Point Vector;
const double eps = 1e-10;
int dcmp(double x){
if(fabs(x) < eps) return 0;
else return x < 0 ? -1: 1;
}
double Dot(Vector A, Vector B) { return real(conj(A)*B); }
double Cross(Vector A, Vector B) { return imag(conj(A)*B); }
Vector Rotate(Vector A, double rad) { return A*exp(Point(0,rad)); }
double Length(Vector A) { return sqrt(Dot(A,A)); }
double Angle(Vector A, Vector B) { return acos(Dot(A, B)/Length(A)/Length(B)); } //叉积
double Area2(Point A, Point B, Point C) { return Cross(B-A,C-A); } //有向面积
/*Point模板部分*/

Point GetLineIntersection(Point P, Vector v, Point Q, Vector w){ //两直线的交点，前提是Cross(v,w)!=0
Vector u=P-Q;
double t=Cross(w,u)/Cross(v,w);
return P+v*t;
}
double DistanceToLine(Point P, Point A, Point B){ //P到直线A-B距离
Vector v1=B-A, v2=P-A;
return fabs(Cross(v1,v2) / Length(v1));
}
double DistanceToSegment(Point P, Point A, Point B){ //P到线段A-B距离
if(A==B) return Length(P-A);
Vector v1=B-A, v2=P-A, v3=P-B;
if(dcmp(Dot(v1,v2)) < 0) return Length(v2);
else if(dcmp(Dot(v1,v3)) > 0) return Length(v3);
else return fabs(Cross(v1,v2)) / Length(v1);
}
Point GetLineProjection(Point P, Point A, Point B){ //求P到直线A-B垂点
Vector v=B-A;
return A+v*(Dot(v,P-A)) / Dot(v,v);
}
bool SegmentProPerIntersection(Point a1, Point a2, Point b1,Point b2){ //两线是否规范相交
double c1=Cross(a2-a1,b1-a1), c2=Cross(a2-a1,b2-a1),
c3=Cross(b2-b1,a1-b1), c4=Cross(b2-b1,a2-b1);
return dcmp(c1)*dcmp(c2)<0 && dcmp(c3)*dcmp(c4)<0;
}
bool OnSegment(Point p, Point a1, Point a2){ //p点是否在a1,a2线段上(不在a1,a2点上)
return dcmp(Cross(a1-p,a2-p))==0 && dcmp(Dot(a1-p,a2-p)) < 0;
}
istream& operator >> (istream& in,Point& p){
double a,b;
in>>a>>b;
p=Point(a,b);
return in;
}
Point getD(Point A, Point B, Point C){
Vector Vbc=C-B;
double rad1=Angle(A-B,Vbc);
Vector v1=Rotate(Vbc,rad1/3);

Vector Vcb=B-C;
double rad2=Angle(A-C,Vcb);
Vector v2=Rotate(Vcb,-rad2/3); //clockwise

return GetLineIntersection(B,v1,C,v2);
}
void PrintPoint(Point p){
printf("%.6lf %.6lf", real(p),imag(p));
}
int main(int argc, char const *argv[])
{
int T; scanf("%d",&T);
while(T--){
Point a,b,c,D,E,F;
cin>>a>>b>>c;
D=getD(a,b,c);
E=getD(b,c,a);
F=getD(c,a,b);
PrintPoint(D); putchar(' ');
PrintPoint(E); putchar(' ');
PrintPoint(F); putchar('\n');
}
return 0;
}