直线的旋转与相交，计算几何（Morley定理，uva 11178）

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计算几何基础题

以后还是少瞄答案，看分析做没用的，把分析以下的部分遮住即可。

代码

#include<bits/stdc++.h>using namespace std;struct Point{    double x,y;    Point(double x=0,double y=0):x(x),y(y){}};typedef Point Vector;Point read(){    double x,y;    scanf("%lf %lf",&x,&y);    return Point(x,y);}Vector operator - (Point A,Point B){    return Vector(A.x-B.x,A.y-B.y);}Vector operator * (double t,Vector A){    return Vector(A.x*t,A.y*t);}Point operator + (Point A,Vector B){    return Point(A.x+B.x,A.y+B.y);}double Cross(Vector A,Vector B){    return A.x*B.y-A.y*B.x;}Point GetInterSection(Point P,Vector v,Point Q,Vector w){    Vector u=P-Q;    double t1=Cross(w,u)/Cross(v,w);    return P+t1*v;}Vector Rotate(Vector A,double rad){    return Vector(A.x*cos(rad)-A.y*sin(rad),A.x*sin(rad)+A.y*cos(rad));}double Dot(Point A,Point B){    return A.x*B.x+A.y*B.y;}double Len(Vector A){    return sqrt(Dot(A,A));}double GetAngle(Vector A,Vector B){    return acos(Dot(A,B)/Len(A)/Len(B));}Point GetD(Point A,Point B,Point C){    double rad=GetAngle(A-B,C-B);    rad/=3;    Vector v1=C-B;    v1=Rotate(v1,rad);    rad=GetAngle(A-C,B-C);    rad/=3;    Vector v2=B-C;    v2=Rotate(v2,-rad);    return GetInterSection(B,v1,C,v2);}int main(){    int N;    Point A,B,C,D,E,F;    scanf("%d",&N);    while(N--)    {        A=read();        B=read();        C=read();        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;}

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