1 #include <iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<stdlib.h> 6 #include<vector> 7 #include<cmath> 8 #include<queue> 9 #include<set>10 using namespace std;11 #define N 31012 #define LL long long13 #define INF 1e814 const double eps = 1e-5;15 const double pi = acos(-1.0);16 const double inf = ~0u>>2;17 struct point18 {19     double x,y;20     double vx,vy;21 }p[N],pp[N];22 int n;23 double dis(point a,point b)24 {25     return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));26 }27 double calc(double tt)28 {29     int i,j;30     for(i = 1 ; i <= n; i++)31     {32         pp[i].x=p[i].x+tt*p[i].vx;33         pp[i].y=p[i].y+tt*p[i].vy;34     }35     double ans = 0.0;36     for(i = 1 ; i <= n; i++)37     {38         for(j = 1 ; j <= n ;j++)39         ans = max(ans,dis(pp[i],pp[j]));40     }41     return ans;42 }43 void solve(int k)44 {45     double M,RM;46     double L = 0.0;47     double R = INF;48     while (L + eps < R)49     {50         M = (L + R) / 2;51         RM = (M + R) / 2;52         double s1 = calc(M);53         double s2 = calc(RM);54         if ( s1 < s2 ) R = RM;55         else L = M;56     }57     printf("Case #%d: ",k);58     printf("%.2f %.2f\n",R,calc(R));59 }60 int main()61 {62     int t,i;63     int kk = 0;64     cin>>t;65     while(t--)66     {67         scanf("%d",&n);68         for(i = 1; i <= n ;i++)69         scanf("%lf%lf%lf%lf",&p[i].x,&p[i].y,&p[i].vx,&p[i].vy);70         if(n==1)71         {72             printf("0.00 0.00\n");73             continue;74         }75         solve(++kk);76     }77     return 0;78 }