第九周 10.26---11.1

---------10.26

cf又滚粗了--

老是滚粗---还是太笨了啊---

没事--->_<

cf 591 d

http://codeforces.com/problemset/problem/591/D

看了贴吧里面的题解，说是要改参考系，把起点当成不动的，再二分时间

后来写了下不变参考系的，也可以

应该没什么区别的吧，，，

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 #include<vector>
 6 using namespace std;
 7
 8 int x1,y1,x2,y2,v,T;
 9 int vx,vy,wx,wy;
10 const int INF = (1<<30)-1;
11
12 int ok(double x){
13     double  x3,y3;
14     if(x <= T){
15         x3 = 1.0*x1 + x*vx;
16         y3 = 1.0*y1 + x*vy;
17     }
18     if(x > T){
19         x3 = 1.0*x1 + T*vx + (x-T)*wx;
20         y3 = 1.0*y1 + T*vy + (x-T)*wy;
21     }
22     double dis = (x3-x2)*(x3-x2)*1.0 + (y3-y2)*(y3-y2)*1.0;
23     return dis >= v*v*x*x*1.0;
24 }
25
26 void solve() {
27     double l = 0.0,r = 1.0*INF,mid;
28     for(int i = 0;i <= 1000;i++){
29         mid = (l+r)*0.5;
30         if(ok(mid)) l = mid;
31         else r = mid;
32
33     //    printf("l = %lf r = %lf mid = %lf\n",l,r,mid);
34     }
35     printf("%.16lf\n",l);
36 }
37
38 int main(){
39     while(scanf("%d %d",&x1,&y1) != EOF){
40         scanf("%d %d",&x2,&y2);
41         scanf("%d %d",&v,&T);
42         scanf("%d %d",&vx,&vy);
43         scanf("%d %d",&wx,&wy);
44
45         solve();
46
47     }
48     return 0;
49 }