hdu4717The Moving Points(三分）

链接

需要特判一下n=1的时候

精度调太低会超时

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 #include<cmath>
 #include<queue>
 #include<set>
 using namespace std;
 #define N 310
 #define LL long long
 #define INF 1e8
 const double eps = 1e-;
 const double pi = acos(-1.0);
 const double inf = ~0u>>;
 struct point
 {
     double x,y;
     double vx,vy;
 }p[N],pp[N];
 int n;
 double dis(point a,point b)
 {
     return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
 }
 double calc(double tt)
 {
     int i,j;
     for(i =  ; i <= n; i++)
     {
         pp[i].x=p[i].x+tt*p[i].vx;
         pp[i].y=p[i].y+tt*p[i].vy;
     }
     double ans = 0.0;
     for(i =  ; i <= n; i++)
     {
         for(j =  ; j <= n ;j++)
         ans = max(ans,dis(pp[i],pp[j]));
     }
     return ans;
 }
 void solve(int k)
 {
     double M,RM;
     double L = 0.0;
     double R = INF;
     while (L + eps < R)
     {
         M = (L + R) / ;
         RM = (M + R) / ;
         double s1 = calc(M);
         double s2 = calc(RM);
         if ( s1 < s2 ) R = RM;
         else L = M;
     }
     printf("Case #%d: ",k);
     printf("%.2f %.2f\n",R,calc(R));
 }
 int main()
 {
     int t,i;
     int kk = ;
     cin>>t;
     while(t--)
     {
         scanf("%d",&n);
         for(i = ; i <= n ;i++)
         scanf("%lf%lf%lf%lf",&p[i].x,&p[i].y,&p[i].vx,&p[i].vy);
         if(n==)
         {
             printf("0.00 0.00\n");
             continue;
         }
         solve(++kk);
     }
     return ;
 }