HDU3400+三分

三分出两个中间的位置即可。

 1 /*

 2 两次三分

 3 */

 4 #include<stdio.h>

 5 #include<string.h>

 6 #include<stdlib.h>

 7 #include<math.h>

 8 #include<algorithm>

 9 using namespace std;

10 const int maxn = 105;

11 const double eps = 1e-8;

12 const double pi = acos(-1.0);

13 struct Point {

14     double x,y;

15 };

16 Point a,b,c,d;

17 double P,Q,R,ans1,ans2;

18 

19 double dis( Point aa,Point bb ){

20     return sqrt( (aa.x-bb.x)*(aa.x-bb.x)+(aa.y-bb.y)*(aa.y-bb.y) );

21 }

22 

23 double GetAns( double tt1,double tt2 ){

24     double ans;

25     Point temp1,temp2;

26     temp1.x = a.x+tt1*(b.x-a.x),temp1.y = a.y+tt1*(b.y-a.y);

27     temp2.x = c.x+tt2*(d.x-c.x),temp2.y = c.y+tt2*(d.y-c.y);

28     ans = dis( a,temp1 )/P+dis( temp1,temp2 )/R+dis( temp2,d )/Q;

29     return ans;

30 }

31 

32 double solve( double x ){

33     double L,R,mid1,mid2;

34     L = 0;

35     R = 1;

36     while( R-L>eps ){

37         mid1 = (L+R)/2.0;

38         mid2 = (mid1+R)/2.0;

39         if( GetAns( x,mid1 )<GetAns( x,mid2 ) ){

40             ans2 = mid1;

41             R = mid2;

42         }

43         else{

44             ans2 = mid2;

45             L = mid1;

46         }

47     }

48     return GetAns( x,ans2 );

49 }

50 

51 int main(){

52     int T;

53     scanf("%d",&T);

54     while( T-- ){

55         scanf("%lf%lf%lf%lf",&a.x,&a.y,&b.x,&b.y);

56         scanf("%lf%lf%lf%lf",&c.x,&c.y,&d.x,&d.y);

57         scanf("%lf%lf%lf",&P,&Q,&R);

58         double L,R,mid1,mid2;

59         L = 0;

60         R = 1;

61         while( R-L>eps ){

62             mid1 = (L+R)/2.0;

63             mid2 = (mid1+R)/2.0;

64             if( solve( mid1 )<solve( mid2 ) ){

65                 ans1 = mid1;

66                 R = mid2;

67             }

68             else{

69                 ans1 = mid2;

70                 L = mid1;

71             }

72         }

73         printf("%.2lf\n",GetAns( ans1,ans2 ));

74     }

75     return 0;

76 }

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