hdu 5112 (2014北京现场赛 A题)

给出某个时刻对应的速度 求出相邻时刻的平均速度 输出最大值

Sample Input
2
3 // n
2 2 //t v
1 1
3 4
3
0 3
1 5
2 0

Sample Output
Case #1: 2.00
Case #2: 5.00

 # include <iostream>
 # include <cstdio>
 # include <cstring>
 # include <algorithm>
 # include <string>
 # include <cmath>
 # include <queue>
 # include <list>
 # define LL long long
 using namespace std ;

 struct point
 {
     int t ;
     int v ;
 }a[];

 bool cmp(point x , point y)
 {
     return x.t < y.t ;
 }

 int main()
 {
     //freopen("in.txt","r",stdin) ;
     int T ;
     scanf("%d" , &T) ;
     int Case =  ;
     while(T--)
     {
         int n , i ;
         Case++ ;
         double MAX =  ;
         scanf("%d" , &n) ;
         for (i =  ; i < n ; i++)
            scanf("%d %d" , &a[i].t , &a[i].v) ;
         sort(a , a+n , cmp) ;
         for (i =  ; i < n- ; i++)
         {
             double ans = fabs((a[i+].v - a[i].v)*1.0/(a[i+].t - a[i].t)*1.0) ;
             if (ans > MAX)
                 MAX = ans ;
         }
         printf("Case #%d: %.2lf\n" , Case , MAX) ;

     }

     return  ;
 }