1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <cmath> 5 using namespace std; 6  7 const double eps = 1e-8; 8 struct Point3//三维空间点 9 {10     double x, y, z;11     Point3(double x=0,double y=0,double z=0): x(x),y(y),z(z){}12     Point3 operator + (Point3 &t){return Point3(x+t.x, y+t.y, z+t.z);}13     Point3 operator - (Point3 &t) {return Point3(x-t.x, y-t.y, z-t.z);}14     Point3 operator * (double p) {return Point3(x*p, y*p, z*p);}15     Point3 operator / (double p) {return Point3(x/p, y/p, z/p);}16 };17 typedef Point3 Vector3;18 struct Line//空间直线19 {20     Point3 a,b;21 };22 int dcmp(double x)23 {24     if(fabs(x) < eps) return 0;25     return x < 0 ? -1 : 1;26 }27 double Dot(Vector3 A,Vector3 B) { return A.x*B.x + A.y*B.y + A.z*B.z; }28 double Length2(Vector3 A) { return Dot(A, A); }29 Vector3 Cross(Vector3 A, Vector3 B) { return Vector3(A.y*B.z - A.z*B.y, A.z*B.x - A.x*B.z, A.x*B.y - A.y*B.x); }30 inline double min(double a,double b)31 {32     if(dcmp(b-a)>=0) return a;33     return b;34 }35 double LineToLine(Line u,Line v)//空间直线间距离36 {37     Vector3 t=Cross(u.a-u.b,v.a-v.b);38     return fabs(Dot(u.a-v.a,t))/sqrt(Length2(t));39 }40 41 Line L[35];42 double R[35];43 44 void init(int i)45 {46     Point3 a,b,c;47     scanf("%lf%lf%lf%lf%lf%lf%lf%lf%lf",&a.x,&a.y,&a.z,&b.x,&b.y,&b.z,&c.x,&c.y,&c.z);48     Vector3 n=Cross(b-a,c-a);//平面法向量49     L[i].a=a;L[i].b=a+n;R[i]=sqrt(Length2(b-a));50 }51 52 int main()53 {54     int T,i,j,n;55     scanf("%d",&T);56     while(T--)57     {58         scanf("%d",&n);59         for(i=0;i<n;i++) init(i);60         bool flag=0;61         double ans=1e20;62         for(i=0;i<n&&!flag;i++)63         {64             for(j=i+1;j<n&&!flag;j++)65             {66                 double temp=LineToLine(L[i],L[j]);67                 if(dcmp(R[i]+R[j]-temp)>=0)68                     flag=1;69                 else ans=min(ans,temp-R[i]-R[j]);70             }71         }72         if(flag) printf("Lucky\n");73         else printf("%.2lf\n",ans);74     }75     return 0;76 }