FatMouse
时间限制：1 秒
内存限制：128 兆
特殊判题：否
提交：1431
解决：641
- 题目描述：
-
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.
- 输入：
-
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.
- 输出：
-
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.
- 样例输入：
- 5 3
7 2
4 3
5 2
20 3
25 18
24 15
15 10
-1 -1
- 样例输出：
- 13.333
31.500
1 #include <iostream> 2 #include <algorithm> 3 #include <iomanip> 4 using namespace std; 5 6 struct goods 7 { 8 int J,F; 9 double xinjia; 10 }buf[1000]; 11 12 13 bool cmp(goods a,goods b) 14 { 15 16 return a.xinjia<b.xinjia; 17 } 18 19 20 int main() 21 { 22 int m,n,j,f; 23 while(cin>>m) 24 { 25 cin>>n; 26 if(m==-1&&n==-1) break; 27 int i; 28 for(i=0;i<n;i++) 29 { 30 cin>>j>>f; 31 buf[i].J=j; 32 buf[i].F=f; 33 buf[i].xinjia=(double)f/j; 34 } 35 sort(buf,buf+n,cmp); 36 37 double sum=0.0; 38 for(i=0;i<n;i++) 39 { 40 if(buf[i].F<m) 41 { 42 sum=sum+buf[i].J; 43 m=m-buf[i].F; 44 } 45 else 46 { 47 sum=sum+buf[i].J*(double)m/buf[i].F; 48 break; 49 } 50 } 51 52 cout<<fixed<<setprecision(3)<<sum<<endl; 53 54 55 } 56 return 0; 57 } 58 59 /************************************************************** 60 Problem: 1433 61 User: 2009declan 62 Language: C++ 63 Result: Accepted 64 Time:10 ms 65 Memory:1536 kb 66 ****************************************************************/
