【HDOJ】3400 Line belt

三分。

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <cmath>
 4
 5 typedef struct {
 6     double x, y;
 7 } Point_t;
 8
 9 Point_t A, B, C, D;
10 const double eps = 1.0e-8;
11 double P, Q, R;
12
13 double dist(Point_t a, Point_t b) {
14     return sqrt((a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y));
15 }
16
17 double t_ab(Point_t a, Point_t b) {
18     return dist(a, b)/P;
19 }
20
21 double t_cd(Point_t c, Point_t d) {
22     return dist(c, d)/Q;
23 }
24
25 double t_oth(Point_t x, Point_t y) {
26     return dist(x, y)/R;
27 }
28
29 double tri_cd(Point_t c, Point_t d, Point_t S) {
30     Point_t left = c, right = d;
31     Point_t p1, p2;
32
33     while (dist(left, right) > eps) {
34         p1.x = left.x*2.0/3.0 + right.x/3.0;
35         p1.y = left.y*2.0/3.0 + right.y/3.0;
36         p2.x = left.x/3.0 + right.x*2.0/3.0;
37         p2.y = left.y/3.0 + right.y*2.0/3.0;
38         if (t_oth(S, p1)+t_cd(p1, D) <= t_oth(S, p2)+t_cd(p2, D)) {
39             right = p2;
40         } else {
41             left = p1;
42         }
43     }
44     return t_oth(S, left) + t_cd(left, d);
45 }
46
47 double tri_ab(Point_t a, Point_t b) {
48     Point_t left = a, right = b;
49     Point_t p1, p2;
50
51     while (dist(left, right) > eps) {
52         p1.x = left.x*2.0/3.0 + right.x/3.0;
53         p1.y = left.y*2.0/3.0 + right.y/3.0;
54         p2.x = left.x/3.0 + right.x*2.0/3.0;
55         p2.y = left.y/3.0 + right.y*2.0/3.0;
56         if (t_ab(a, p1)+tri_cd(C, D, p1) <= t_ab(a, p2)+tri_cd(C, D, p2)) {
57             right = p2;
58         } else {
59             left = p1;
60         }
61     }
62     return t_ab(a, left) + tri_cd(C, D, left);
63 }
64
65 int main() {
66     int t;
67
68     scanf("%d", &t);
69     while (t--) {
70         scanf("%lf%lf%lf%lf",&A.x,&A.y,&B.x,&B.y);
71         scanf("%lf%lf%lf%lf",&C.x,&C.y,&D.x,&D.y);
72         scanf("%lf%lf%lf", &P, &Q, &R);
73         printf("%.2lf\n", tri_ab(A, B));
74     }
75
76     return 0;
77 }