CDZSC_2015寒假新人（1）——基礎 C

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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 37 24 35 220 325 1824 1515 10-1 -1              

Sample Output

13.33331.500 

#include <iostream>#include <cstdio>#include <algorithm>using namespace std;struct laoshu{    int j;    int f;    double s;};bool cmp(laoshu stud1,laoshu stud2){    return stud1.s>stud2.s;}int main(){#ifdef CDZSC_OFFLINE    freopen("in.txt","r",stdin);#endif    int i,m,n;    double sum;    laoshu stud[1010];    while(scanf("%d%d",&m,&n)&&m!=-1&&n!=-1)    {        sum=0;        for(i=0; i<n; i++)        {            scanf("%d%d",&stud[i].j,&stud[i].f);            stud[i].s=1.0*stud[i].j/stud[i].f;        }        sort(stud,stud+n,cmp);        for(i=0; i<n; i++)        {            if(m>=stud[i].f)            {                sum+=stud[i].j;                m-=stud[i].f;            }            else            {                sum+=stud[i].s*m;                break;            }        }        printf("%.3lf\n",sum);    }    return 0;}

 

CDZSC_2015寒假新人（1）——基礎 C