HDU4741

#include <iostream>
#include <math.h>
#include <iomanip>
#include <algorithm>

#define eps 1e-8
#define zero(x) (((x)>0?(x):-(x))<eps)

struct point3{ double x, y, z; };
struct line3{ point3 a, b; };
struct plane3{ point3 a, b, c; };

using namespace std;

point3 xmult(point3 u, point3 v)
{
    point3 ret;
    ret.x = u.y*v.z - v.y*u.z;
    ret.y = u.z*v.x - u.x*v.z;
    ret.z = u.x*v.y - u.y*v.x;
    return ret;
}
point3 subt(point3 u, point3 v)
{
    point3 ret;
    ret.x = u.x - v.x;
    ret.y = u.y - v.y;
    ret.z = u.z - v.z;
    return ret;
}
double dmult(point3 u, point3 v)
{
    return u.x*v.x + u.y*v.y + u.z*v.z;
}
double vlen(point3 p)
{
    return sqrt(p.x*p.x + p.y*p.y + p.z*p.z);
}
double linetoline(line3 u, line3 v)
{
    point3 n = xmult(subt(u.a, u.b), subt(v.a, v.b));
    return fabs(dmult(subt(u.a, v.a), n)) / vlen(n);
}
double linetoline(point3 u1, point3 u2, point3 v1, point3 v2)
{
    point3 n = xmult(subt(u1, u2), subt(v1, v2));
    return fabs(dmult(subt(u1, v1), n)) / vlen(n);
}
int main()
{
    int T;
    cin >> T;
    while (T--)
    {
        point3 a, b, c, d;
        cin >> c.x >> c.y >> c.z >> d.x >> d.y >> d.z >> a.x >> a.y >> a.z >> b.x >> b.y >> b.z;
        cout << fixed << setprecision(6) << linetoline(a, b, c, d) << endl;

        double H = b.x - a.x, I = b.y - a.y, J = b.z - a.z;
        double K = d.x - c.x, L = d.y - c.y, M = d.z - c.z;
        double N = H * I * L - I * I * K - J * J * K + H * J * M;
        double O = H * H * L - H * I * K - I * J * M + J * J * L;
        double P = H * J * K - H * H * M - I * I * M + I *J * L;
        double Q = -a.x * N + a.y * O - a.z * P;
        double k = (O * c.y - N * c.x - P * c.z - Q) / (N * K - O * L + P * M);
        cout << fixed << setprecision(6) << K * k + c.x << ' ' << L * k + c.y << ' ' << M * k + c.z << ' ';
        swap(a, c);
        swap(b, d);
        H = b.x - a.x, I = b.y - a.y, J = b.z - a.z;
        K = d.x - c.x, L = d.y - c.y, M = d.z - c.z;
        N = H * I * L - I * I * K - J * J * K + H * J * M;
        O = H * H * L - H * I * K - I * J * M + J * J * L;
        P = H * J * K - H * H * M - I * I * M + I *J * L;
        Q = -a.x * N + a.y * O - a.z * P;
        k = (O * c.y - N * c.x - P * c.z - Q) / (N * K - O * L + P * M);
        cout << fixed << setprecision(6) << K * k + c.x << ' ' << L * k + c.y << ' ' << M * k + c.z << endl;
    }
}

补充：软件开发 , C++ ,

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