[SCOI 2005] 栅栏

#include<bits/stdc++.h>
using namespace std;
#define MAXM 55
#define MAXN 1010

int i,n,m,l,r,ans,mid,total,w;
int a[MAXM],b[MAXN],cnt[MAXN];

inline bool dfs(int dep,int last)
{
    int i,pos;
    bool flag = false;
    if (dep == 0) return true;
    if (w > total - cnt[mid]) return false;
    for (i = last; i <= m; i++)
    {
        if (a[i] >= b[dep])
        {
            a[i] -= b[dep];
            if (a[i] < b[1]) w += a[i];
            if (b[dep - 1] == b[dep]) flag = dfs(dep - 1,i);
            else flag = dfs(dep - 1,1);
            if (a[i] < b[1]) w -= a[i];
            a[i] += b[dep];
            if (flag) return true;
        } 
    }
    return false;
}
inline bool check(int m)
{
    w = 0;
    if (dfs(m,1)) return true;
    else return false;
}

int main()
{
    
    scanf("%d",&m);
    for (i = 1; i <= m; i++) 
    {
        scanf("%d",&a[i]);
        total += a[i];
    }
    scanf("%d",&n);
    for (i = 1; i <= n; i++) scanf("%d",&b[i]);
    sort(a+1,a+m+1);
    sort(b+1,b+n+1);
    for (i = 1; i <= n; i++) cnt[i] = cnt[i - 1] + b[i]; 
    l = 1; r = n;
    while (l <= r)
    {
        mid = (l + r) >> 1;
        if (check(mid))
        {
            ans = mid;
            l = mid + 1;
        } else r = mid - 1;
    }
    printf("%d\n",ans);
    
    return 0;    
}