hdu 1114 Piggy-Bank 完全背包基础题

#include <stdio.h>
#include <string.h>
#define INF 1000000000
int min(int a,int b)
{
    return a<b?a:b;
}
int c[505],w[505];
int f[10001];
int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        int l,r,n,m,i,j,k;
        scanf("%d%d",&l,&r);
        m=r-l;
        scanf("%d",&n);
        for(i=0;i<=m;i++)
            f[i]=INF;
        f[0]=0;
        for(i=0;i<n;i++)
            scanf("%d%d",&w[i],&c[i]);
        for(i=0;i<n;i++)
        {
            for(j=c[i];j<=m;j++)
                if(f[j-c[i]]!=INF)
                f[j]=min(f[j],f[j-c[i]]+w[i]);
        }
        if(f[m]==INF)
            printf("This is impossible.\n");
        else
            printf("The minimum amount of money in the piggy-bank is %d.\n",f[m]);
    }
    return 0;
}

题意：一个储钱罐，知道初始质量和装满钱的质量，之后知道各种钱的价值和质量，问存钱罐中至少有多少钱