HDU 2844 (多重背包)

#include <bits/stdc++.h>
using namespace std;
#define maxn 111111

bool dp[maxn];
int a[maxn];
int p[maxn], tot, n, m;

int main () {
    //freopen ("in", "r", stdin);
    while (scanf ("%d%d", &n, &m) == 2 && n+m) {
        for (int i = 1; i <= n; i++) {
            scanf ("%d", &a[i]);
        }
        tot = 0;
        for (int id = 1; id <= n; id++) {
            int cnt;
            scanf ("%d", &cnt);
            for (int i = 1; i <= cnt; i <<= 1) {
                p[tot++] = i*a[id];
                cnt -= i;
            }
            if (cnt > 0) {
                p[tot++] = cnt*a[id];
            }
        }
        memset (dp, 0, sizeof dp);
        dp[0] = 1;
        for (int i = 0; i < tot; i++) {
            for (int j = m-p[i]; j >= 0; j--) {
                dp[j+p[i]] = ((dp[j] == 1)|dp[j+p[i]]);
            }
        }
        int ans = 0;
        for (int i = 1; i <= m; i++) {
            if (dp[i]) {
                ans++;
            }
        }
        printf ("%d\n", ans);
    }
    return 0;
}