BZOJ 1082 暴搜

思路：

//By SiriusRen
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
int n,m,st=1,a[6666],b[6666],l,r,ans,vis[6666],Mid,tot,sum[6666];
bool dfs(int x,int pos,int waste){
    if(!x)return 1;
    if(waste+sum[Mid]>tot)return 0;
    bool flag=0;
    for(int i=pos;i<=m;i++)
        if(a[i]-b[x]>=0){
            a[i]-=b[x];
            if(a[i]<b[1])waste+=a[i];
            if(b[x]==b[x-1])flag=dfs(x-1,i,waste);
            else flag=dfs(x-1,1,waste);
            if(a[i]<b[1])waste-=a[i];
            a[i]+=b[x];
            if(flag)return 1;
        }
    return 0;
}
int main(){
    scanf("%d",&m);
    for(int i=1;i<=m;i++)scanf("%d",&a[i]);
    sort(a+1,a+1+m);
    scanf("%d",&n);
    for(int i=1;i<=n;i++)scanf("%d",&b[i]);
    sort(b+1,b+1+n);
    while(b[n]>a[m])n--;
    for(int i=1;i<=n;i++)sum[i]=sum[i-1]+b[i];
    while(a[st]<b[1])st++;
    for(int i=st;i<=m;i++)a[i-st+1]=a[i],tot+=a[i-st+1];
    m=m-st+1;
    l=0,r=n;
    while(l<=r){
        Mid=(l+r)>>1;
        if(dfs(Mid,1,0))ans=Mid,l=Mid+1;
        else r=Mid-1;
    }
    printf("%d\n",ans);
}