UVA 11178 /// 向量旋转 两向量夹角

#include <bits/stdc++.h>
using namespace std;const double eps=1e-;
double add(double a,double b) {
if(abs(a+b)<eps*(abs(a)+abs(b))) return ;
return a+b;
}
struct P {
double x,y;
P(){}
P(double _x,double _y):x(_x),y(_y){}
P operator - (P p) {
return P(add(x,-p.x),add(y,-p.y)); }
P operator + (P p) {
return P(add(x,p.x),add(y,p.y)); }
P operator / (double d) {
return P(x/d,y/d); }
P operator * (double d) {
return P(x*d,y*d); }
double dot (P p) {
return add(x*p.x,y*p.y); }
double det (P p) {
return add(x*p.y,-y*p.x); }
bool operator <(const P& p)const {
return x<p.x || (x==p.x && y<p.y);
}
bool operator ==(const P& p)const {
return abs(x-p.x)<eps && abs(y-p.y)<eps;
}
void read(){
scanf("%lf%lf",&x,&y); }
void ptf() {
printf("%.6f %.6f ",&x,&y); }
};double lenP(P a) {
return sqrt(a.dot(a));
}
double Angle(P a,P b) {
return acos(a.dot(b)/lenP(a)/lenP(b));
} /// a.dot(b)=|a||b|cos(ang)
P Rotate(P a,double rad) {
P r=P(sin(rad),cos(rad));
return P(a.det(r),a.dot(r));
}
P ins(P a,P v1,P b,P v2) {
P v=a-b;
double t=v2.det(v)/v1.det(v2);
return a+v1*t;
}
P insGet(P a,P b,P c) {
double a1=Angle(a-b,c-b);
P v1=Rotate(c-b,a1/3.0); /// 向量bc绕b逆时针旋转a1/3角度 double a2=Angle(a-c,b-c);
P v2=Rotate(b-c,-a2/3.0); /// 向量cb绕c顺时针旋转a2/3角度
return ins(b,v1,c,v2);
}int main()
{
int t; scanf("%d",&t);
while(t--) {
P a,b,c,d,e,f;
a.read(), b.read(), c.read();
d=insGet(a,b,c);
e=insGet(b,c,a);
f=insGet(c,a,b);
d.ptf(), e.ptf(), f.ptf();
printf("\n");
} return ;
}