Morley's Theorem

题解：

计算几何基本操作

注意叉积的时候字母写的顺序

代码：

#include <bits/stdc++.h>
using namespace std;
#define rint register int
#define IL inline
#define rep(i,h,t) for (int i=h;i<=t;i++)
#define dep(i,t,h) for (int i=t;i>=h;i--)
const double eps=1e-;
struct Point
{
  double x,y;
  Point(double x1,double y1) {x=x1,y=y1;}
  Point(){};
  Point operator +(const Point b) const
  {
    return Point(x+b.x,y+b.y);
  }
  Point operator -(const Point b) const
  {
    return Point(x-b.x,y-b.y);
  }
  double operator *(const Point b) const
  {
    return x*b.x+y*b.y;
  }
  double operator ^(const Point b) const
  {
    return x*b.y-y*b.x;
  }
  Point operator *(double k)
  {
    return Point(x*k,y*k);
  }
  Point operator /(double k)
  {
    return Point(x/k,y/k);
  }
  bool operator ==(Point b)
  {
    return b.x==x&&b.y==y?:;
  }
};
struct Line
{
  Point x,y;
  Line() {};
  Line(Point x1,Point y1){x=x1,y=y1;};
};
double lenth(Point x)
{
  return sqrt(x.x*x.x+x.y*x.y);
}
double angle(Point x,Point y)
{
  return acos(x*y/lenth(x)/lenth(y));
}
int dcmp(double x)
{
  if (x<-eps) return(-);
  else if (x>eps) return();
  else return();
}
Point rotate(Point x,double r)
{
  return Point(x.x*cos(r)-x.y*sin(r),x.x*sin(r)+x.y*cos(r));
}
Point gtp(Line x,Line y)
{
  Point v1=x.y-x.x; Point v2=y.y-y.x;
  double k=((x.x^v1)-(y.x^v1))/(v2^v1);
  return y.x+v2*k;
}
double distance(Point x,Line y)
{
  Point p1=x-y.x,p2=y.y-y.x;
  return fabs((p1^p2)/lenth(p2));
}
Point get(Point a,Point b,Point c)
{
  Point v1,v2;
  double r1=angle(a-b,c-b);
  v1=rotate(c-b,r1/); v1=v1+b;
  double r2=angle(a-c,b-c);
  v2=rotate(b-c,-r2/); v2=v2+c;
  return gtp(Line(b,v1),Line(c,v2));
}
int main()
{
  freopen("1.in","r",stdin);
  freopen("1.out","w",stdout);
  ios::sync_with_stdio(false);
  int T;
  cin>>T;
  while (T--)
  {
    int a1,a2,a3,b1,b2,b3;
    cin>>a1>>b1>>a2>>b2>>a3>>b3;
    Point p1,p2,p3,a,b,c;
    p1=Point(a1,b1); p2=Point(a2,b2); p3=Point(a3,b3);
    a=get(p1,p2,p3); b=get(p2,p3,p1); c=get(p3,p1,p2);
    printf("%.6lf %.6lf %.6lf %.6lf %.6lf %.6lf\n",
    a.x,a.y,b.x,b.y,c.x,c.y);
  }
  return ;
}