FatMouse‘ Trade(贪心算法)

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

#include
typedef struct
{
    double value;
    double price;
    double food;
} f;
int main()
{
    int m,n,i,r,k;
    double a,b,t,p,x=0,l;
    f c[1000];
    scanf("%d%d",&m,&n);
    while(m!=-1&&n!=-1)
    {
        for(i=0; ic[k].value)
                    k=r;
            }
            f t;
            t=c[k];

            c[k]=c[i];

            c[i]=t;

        }
        for(i=0; i=c[i].price)
            {
                x+=c[i].food;
                m=m-c[i].price;
                continue;

            }
            if(m