HDU 1203 I NEED A OFFER! (背包的多项式操作)

#include<iostream>
#include<stdio.h>
#include<cstring>
using namespace std;
int m;
double dp[10001];

double f(double x,double y)
{
return 1-(1-x)*(1-y);
}

void ZeroOnePack(int cost, double weight)
{
for (int i = m; i >= cost; i--)
dp[i] = max(dp[i], f(dp[i-cost],weight));
}

int main()
{
int n;
while(cin>>m>>n)
{
memset(dp,0,sizeof(dp));
if(!m&&!n)
break;
for(int i=1;i<=n;i++)
{
int a;
double b;
cin>>a>>b;
ZeroOnePack(a,b);
}
printf("%.1lf%%\n",dp[m]*100);
}
return 0;
}