hdu 1009 FatMouse' Trade
FatMouse' Trade
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 63732 Accepted Submission(s): 21565
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.
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
Author
CHEN, Yue
Source
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include<iostream> #include<stdio.h> #include<algorithm> using namespace std; struct Node { double f,j; double wei; }room[100005]; bool cmp(Node a,Node b) { return a.wei>b.wei; } int main() { double m; int n; while(scanf("%lf%d",&m,&n)&&(m!=-1&&n!=-1)) { for(int i=0;i<n;i++) { scanf("%lf%lf",&room[i].j,&room[i].f); room[i].wei=room[i].j/room[i].f; } sort(room,room+n,cmp); double ans=0; for(int i=0;i<n;i++) { if(m<=0) break; if(m>=room[i].f) {m-=room[i].f;ans+=room[i].j;} else if(m<room[i].f){ans+=m*room[i].wei;m-=m;break;} } printf("%.3lf\n",ans); } }
简单的贪心,没什么好说的。