hdu 1009 FatMouse' Trade

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 #include<algorithm>
 4 using namespace std;
 5 const int MAXN = 1010;
 6 struct node
 7 {
 8     double j,f;
 9     double r;
10 }a[MAXN];
11 bool cmp(node a,node b)
12 {
13     return a.r  >  b.r;
14 }    
15 int main()
16 {
17     int N;
18     double M;
19     double ans;
20     while(scanf("%lf%d",&M,&N))
21     {
22         if(M==-1&&N==-1) break;
23         for(int i=0;i<N;i++)
24         {
25            scanf("%lf%lf",&a[i].j,&a[i].f);
26            a[i].r=(double)a[i].j/a[i].f;
27         }    
28         sort(a,a+N,cmp);
29         ans=0;
30         for(int i=0;i<N;i++)
31         {
32             if(M>=a[i].f)
33             {
34                 ans+=a[i].j;
35                 M-=a[i].f;
36             }    
37             else 
38             {
39                 ans+=(a[i].j/a[i].f)*M;
40                 break;
41             }    
42         }   
43         printf("%.3lf
",ans); 
44     }    
45     return 0;
46 }

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FatMouse' Trade

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 80808 Accepted Submission(s): 27951

Problem Description

FatMouse prepared M pounds of cat food, ready to trade with the cats guarding the warehouse containing his favorite food, JavaBean.
The warehouse has N rooms. The i-th room contains J[i] pounds of JavaBeans and requires F[i] pounds of cat food. FatMouse does not have to trade for all the JavaBeans in the room, instead, he may get J[i]* a% pounds of JavaBeans if he pays F[i]* a% pounds of cat food. Here a is a real number. Now he is assigning this homework to you: tell him the maximum amount of JavaBeans he can obtain.

Input

The input consists of multiple test cases. Each test case begins with a line containing two non-negative integers M and N. Then N lines follow, each contains two non-negative integers J[i] and F[i] respectively. The last test case is followed by two -1's. All integers are not greater than 1000.

Output

For each test case, print in a single line a real number accurate up to 3 decimal places, which is the maximum amount of JavaBeans that FatMouse can obtain.

Sample Input

5 3 7 2 4 3 5 2 20 3 25 18 24 15 15 10 -1 -1

Sample Output

13.333 31.500