欧拉四面体公式:
void Solve(){double a, b, c, m, n, l;scanf("%lf%lf%lf%lf%lf%lf", &a, &c, &b, &n, &l, &m);double V = (double)sqrt((4.0*a*a*b*b*c*c-a*a*(b*b+c*c-m*m)*(b*b+c*c-m*m)- b*b*(c*c+a*a-n*n)*(c*c+a*a-n*n)-c*c*(a*a+b*b-l*l)* (a*a+b*b-l*l)+(a*a+b*b-l*l)*(b*b+c*c-m*m)*(c*c+a*a-n*n)))/12.0;printf("%.4lf ", V);}HDU 1411From:cnblogs GLSilence