HDU 3448 Bag Problem

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;

const int maxn=50;
int LimN;
long long LimV;
int N;
long long v[maxn];
long long ans;

void dfs(int now,int tot,long long sum)
{
    if(sum>ans) ans=sum;
    if(now==N) return;
    if(tot+1>LimN) return;
    if(sum+v[now]>LimV) return;

    dfs(now+1,tot+1,sum+v[now]);
    dfs(now+1,tot,sum);
}

int main()
{
    while(~scanf("%d%lld",&LimN,&LimV))
    {
        scanf("%d",&N);
        for(int i=0; i<N; i++) scanf("%lld",&v[i]);
        sort(v,v+N);
        long long k=0;
        for(int i=N-1;i>=N-min(LimN,N);i--) k=k+v[i];
        if(v[0]>LimV) 
        {
            printf("0\n");
            continue;
        }
        if(k<=LimV)
        {
            printf("%lld\n",k);
            continue;
        }
        ans=0;
        dfs(0,0,0);
        printf("%lld\n",ans);
    }
    return 0;
}