poj1276

多重背包，但由于是bool型，可以使用特殊方法优化效率使得效率与01背包相同

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
using namespace std;

#define maxn 15
#define maxc 100005

int cash;
int n;
int num[maxn], denomination[maxn];
bool f[maxc];
int used[maxc];

void input()
{
    scanf("%d", &n);
    for (int i = 0; i < n; i++)
        scanf("%d%d", &num[i], &denomination[i]);
}

void work()
{
    memset(f, 0, sizeof(f));
    f[0] = true;
    for (int i = 0; i < n; i++)
    {
        memset(used, 0, sizeof(used));
        for (int j = denomination[i]; j <= cash; j++)
            if (f[j - denomination[i]] && !f[j] && used[j - denomination[i]] < num[i])
            {
                f[j] = true;
                used[j] = used[j - denomination[i]] + 1;
            } 
    }
}

int main()
{
    //freopen("t.txt", "r", stdin);
    while (~scanf("%d", &cash))
    {
        input();
        work();
        for (int i = cash; i >= 0; i--)
            if (f[i])
            {
                printf("%d\n", i);
                break;
            }
    }
    return 0;
}