1006 Line belt

Problem Description

In a two-dimensional plane there are two line belts, there are two segments AB and CD, lxhgww's speed on AB is P and on CD is Q, he can move with the speed R on other area on the plane.
How long must he take to travel from A to D?

 

Input

The first line is the case number T.
For each case, there are three lines.
The first line, four integers, the coordinates of A and B: Ax Ay Bx By.
The second line , four integers, the coordinates of C and D:Cx Cy Dx Dy.
The third line, three integers, P Q R.
0<= Ax，Ay，Bx，By，Cx，Cy，Dx，Dy<=1000
1<=P，Q，R<=10

 

Output

The minimum time to travel from A to D, round to two decimals.

 

Sample Input

1
0 0 0 100
100 0 100 100
2 2 1

 

Sample Output

136.60

 

Author

lxhgww&&momodi

#include
#include
#include
#define eps 1e-15
using namespace std;
struct point
{
    double x,y;
};
point A,B,C,D;
double P,Q,R;
int sgn(double a)
{
    return (a>eps)-(a<-eps);
}
double dist(point a,point b)
{
    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
}
double calcu_lin(point a,point b,point c,point d)
{
    return dist(a,b)/P+dist(b,c)/R+dist(c,d)/Q ;
}
point MID(point a,point b)
{
    point c;
    c.x=(a.x+b.x)*0.5;
    c.y=(a.y+b.y)*0.5;
    return c;
}
double sanfen1(point a,point b,point c,point d,point &mid)
{
   point mid1,midmid;
    point l,rr;l=c;rr=d;
    double t1,t2;
   do
   {
     mid1=MID(l,rr);
     midmid=MID(mid1,rr);
     t1=calcu_lin(a,b,mid1,d);
     t2=calcu_lin(a,b,midmid,d);
     if(t1
     rr=midmid;
     else
     l=mid1;
   }
   while(sgn(t1-t2)!=0);
   mid=mid1;
   return  t1;
}
double sanfen2(point d,point c,point b,point a,point &mid)
{
   point mid1,midmid;
    point l,rr;l=a;rr=b;
    double t1,t2;
   do
   {
     mid1=MID(l,rr);
     midmid=MID(mid1,rr);
     t1=calcu_lin(a,mid1,c,d);
     t2=calcu_lin(a,midmid,c,d);
     if(t1
     rr=midmid;
     else
     l=mid1;
   }
   while(sgn(t1-t2)!=0);
   mid=mid1;
   return  t1;
}
void work()
{
    double t1,t2;point mid1,mid2;
    mid1.x=B.x;mid1.y=B.y;
    do
    {
        //printf("okok\n");
      t1=sanfen1(A,mid1,C,D,mid2);
      t2=sanfen2(D,mid2,B,A,mid1);
    }
    while(sgn(t1-t2)!=0);
    printf("%.2lf\n",t1);
}
int main()
{
    int t;
    double ff;
    scanf("%d",&t);
     while(t--)
    {
        scanf("%lf%lf%lf%lf",&A.x,&A.y,&B.x,&B.y);
        scanf("%lf%lf%lf%lf",&C.x,&C.y,&D.x,&D.y);
        scanf("%lf%lf%lf",&P,&Q,&R);
          work();


    }

    return 0;
}