hdu 4741 Save Labman No.004 [2013年杭州ACM网络赛]
#include<iostream>#include<cstdio>#include<cmath>using namespace std;typedef struct point{double x,y,z;point(double xx=0,double yy=0,double zz=0):x(xx),y(yy),z(zz){}}vector;vector operator - (point a,point b){return vector(a.x-b.x,a.y-b.y,a.z-b.z);}point operator + (point a,vector b){return point(a.x+b.x,a.y+b.y,a.z+b.z);}vector operator * (vector a,double b){return vector(a.x*b,a.y*b,a.z*b);}double dot(vector a,vector b){return a.x*b.x+a.y*b.y+a.z*b.z;}double len(vector a){return sqrt(dot(a,a));}vector cross(vector a,vector b){return vector(a.y*b.z-a.z*b.y,a.z*b.x-a.x*b.z,a.x*b.y-a.y*b.x);}point inter(point a,point b,point c,point d,point e){point fa=cross(b-a,c-a);double t=dot(fa,a-d)/dot(fa,e-d);return d+(e-d)*t;}vector resize(vector a,double b){b/=len(a);return a*b;}point ptol(point o,point a,point b){point fa=cross(a-o,b-o);point vec=cross(b-a,fa);return o+resize(vec,len(fa)/len(b-a));}void gc(point a,point b,point c,point d,point &p1,point &p2){point e=d+cross(a-b,c-d);p1=inter(c,d,e,a,b);p2=ptol(p1,c,d);}int main(){int t;point a,b,c,d,p,q;scanf("%d",&t);while(t--){scanf("%lf%lf%lf%lf%lf%lf",&a.x,&a.y,&a.z,&b.x,&b.y,&b.z);scanf("%lf%lf%lf%lf%lf%lf",&c.x,&c.y,&c.z,&d.x,&d.y,&d.z);gc(a,b,c,d,p,q);double l=len(p-q);printf("%.6lf\n",l);printf("%.6lf %.6lf %.6lf %.6lf %.6lf %.6lf\n",p.x,p.y,p.z,q.x,q.y,q.z);}return 0;}