HDU 3400 Line belt （三分套三分）

 1 #include<iostream>
 2 #include<algorithm>
 3 #include<cstring>
 4 #include<cstdio>
 5 #include<vector>
 6 #include<stack>
 7 #include<queue>
 8 #include<cmath>
 9 #include<map>
10 #include<set>
11 using namespace std;
12 typedef long long ll;
13 typedef pair<int,int> pll;
14 const int INF = 0x3f3f3f3f;
15 const int maxn = 300000+5;
16 
17 const double eps=1e-8;
18 
19 struct node
20 {
21     double x,y;
22 }a,b,c,d;
23 
24 double p,q,r;
25 
26 double getdis(node t1, node t2)
27 {
28     return sqrt((t2.y-t1.y)*(t2.y-t1.y)+(t2.x-t1.x)*(t2.x-t1.x));
29 }
30 
31 double solve_cd(node ab)
32 {
33     node mid, midd;
34     node t1=c,t2=d;
35     double d1,d2;
36     do
37     {
38         mid.x=(t1.x+t2.x)/2;
39         mid.y=(t1.y+t2.y)/2;
40         midd.x=(mid.x+t2.x)/2;
41         midd.y=(mid.y+t2.y)/2;
42         d1=getdis(mid,ab)/r+getdis(d,mid)/q;
43         d2=getdis(midd,ab)/r+getdis(d,midd)/q;
44         if(d1<d2)  t2=midd;
45         else t1=mid;
46     }while(getdis(t1,t2)>=eps);
47     return min(d1,d2);
48 }
49 
50 double solve_ab()
51 {
52     node mid, midd;
53     node t1=a,t2=b;
54     double ans1,ans2;
55     do
56     {
57         mid.x=(t1.x+t2.x)/2;
58         mid.y=(t1.y+t2.y)/2;
59         midd.x=(mid.x+t2.x)/2;
60         midd.y=(mid.y+t2.y)/2;
61         double d1=getdis(mid,a);
62         double d2=getdis(midd,a);
63         ans1=d1/p+solve_cd(mid);
64         ans2=d2/p+solve_cd(midd);
65         if(ans1<ans2) t2=midd;
66         else  t1=mid;
67     }while(getdis(t1,t2)>=eps);
68     return min(ans1,ans2);
69 }
70 
71 int main()
72 {
73     //freopen("in.txt","r",stdin);
74     int T;
75     scanf("%d",&T);
76     while(T--)
77     {
78         scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&a.x,&a.y,&b.x,&b.y,&c.x,&c.y,&d.x,&d.y);
79         scanf("%lf%lf%lf",&p,&q,&r);
80         printf("%.2f\n",solve_ab());
81     }
82     return 0;
83 }