by 卡常的hansang:

#include <bits/stdc++.h>
using namespace std;
const int N=55, M=1010;
int a[N], b[M], d, sa[N], sb[M], n, m, sum, w;
bool dfs(int x, int last){
	if(sum - w < sb[d]) return 0;
	if(x == 0) return 1;
	for(int i=last; i <= n; i++) if(sa[i] >= b[x]){
		sa[i] -= b[x]; 
		if(sa[i] < b[1]) w += sa[i];
		if(b[x] == b[x-1]){
			if(dfs(x-1, i)) return 1;
		}
		else if(dfs(x-1, 1)) return 1;
		if(sa[i] < b[1]) w -= sa[i];
		sa[i] += b[x]; 
	}
	return 0;
}
bool check(int mid){
	d = mid; w = 0;
	for(int i=1; i <= n; i++) sa[i] = a[i];
	return dfs(mid, 1);
}
int main(){
	scanf("%d", &n); sum = 0;
	for(int i=1; i <= n; i++) scanf("%d", &a[i]), sum += a[i];
	scanf("%d", &m);
	for(int i=1; i <= m; i++) scanf("%d", &b[i]);
	sort(b+1, b+m+1);
	sb[0] = 0; for(int i=1; i <= m; i++) sb[i] = sb[i-1] + b[i];
	while(sb[m] > sum && m > 0) m--;
	int l = 0, r = m, ans;
	while(l <= r){
		int mid = (l + r) / 2;
		if(check(mid)) l = mid + 1, ans = mid;
		else r = mid - 1;
	}
	printf("%d\n", ans);
	return 0;
}

by 卡常的hansang:

#include<bits/stdc++.h>
using namespace std;
const int N=55, M=1010;
int a[N], b[M], d, sa[N], sb[M], n, m, sum, w;
bool dfs(int x, int last){
	if(sum-w<sb[d]) return 0;
	if(x==0) return 1;
	for(int i=last; i<=n; i++) if(sa[i]>=b[x]){
		sa[i]-=b[x]; 
		if(sa[i]<b[1]) w+=sa[i];
		if(b[x]==b[x-1]){
			if(dfs(x-1, i)) return 1;
		}
		else if(dfs(x-1, 1)) return 1;
		if(sa[i]<b[1]) w-=sa[i];
		sa[i]+=b[x]; 
	}
	return 0;
}
bool check(int mid){
	d=mid; w=0;
	for(int i=1; i<=n; i++) sa[i]=a[i];
	return dfs(mid, 1);
}
int main(){
	scanf("%d", &n); sum=0;
	for(int i=1; i<=n; i++) scanf("%d", &a[i]), sum+=a[i];
	scanf("%d", &m);
	for(int i=1; i<=m; i++) scanf("%d", &b[i]);
	sort(b+1, b+m+1);
	sb[0]=0; for(int i=1; i<=m; i++) sb[i]=sb[i-1]+b[i];
	while(sb[m]>sum && m>0) m--;
	int l=0, r=m, ans;
	while(l<=r){
		int mid=(l+r)/2;
		if(check(mid)) l=mid+1, ans=mid;
		else r=mid-1;
	}
	printf("%d\n", ans);
	return 0;
}