hdu 1009 FatMouse' Trade

最新推荐文章于 2023-03-01 16:25:52 发布

朝向高处的旅途

最新推荐文章于 2023-03-01 16:25:52 发布

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分类专栏： ACM/ICPC

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本文探讨了FatMouse在猫粮交易中最大化获取Java豆的方法，通过贪心算法解决资源分配问题，详细介绍了输入输出规范及算法实现过程。

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FatMouse' Trade

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 33735 Accepted Submission(s): 10987

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

Sample Output

13.333
31.500

一个简单的贪心，就是考考虑特殊数据如果有的不需要花费怎么，如果钱很多，剩下了怎么办。

#include<iostream>
#include<algorithm>
#include<cstdio>
using namespace std;
struct a
{
int j;
int f;
double r;
}s[1010];
bool cmp(struct a m,struct a n)
{
return m.r>n.r;

}

int main()
{
int m,n,i;
while(cin>>m>>n)
{
  if(m==-1 && n==-1) break;
  for(i=0;i<n;i++)
  {
   cin>>s[i].j>>s[i].f;
   if(s[i].f==0)
   {
    s[i].r=1010;

   }
   else
   {
    s[i].r=(double)s[i].j/s[i].f;

   }
  }

sort(s,s+n,cmp);

  int k=0;
  double g=0;
  while(m && k<n)
  {
   if(m>=s[k].f)
   {
    g+=s[k].j;
    m-=s[k].f;
    k++;
   }
   else
   {
    g+=s[k].r*m;
    m=0;

   }

  //if(k==n) break;

  }
  printf("%.3lf\n",g);
}

}