NYOJ--927--dfs--The partial sum problem

/*
    Name: NYOJ--927--The partial sum problem
    Author: shen_渊 
    Date: 15/04/17 19:41
    Description: DFS,和 NYOJ--1058--dfs--部分和问题 基本一致，递归的i+1注意了，其他没什么 
*/

#include<cstring>
#include<iostream>
using namespace std;
void dfs(int);
int arr[22],vis[22];
int n,k,sum,flag;
int main()
{
//    freopen("in.txt","r",stdin);
    while(cin>>n){
        memset(vis,0,sizeof(vis));
        memset(arr,0,sizeof(arr));
        flag = 0;
        for(int i=0; i<n; ++i)cin>>arr[i];
        cin>>k;
        dfs(0);
        if(flag)cout<<"Of course,I can!
";
        else cout<<"Sorry,I can't!
";
    }
    return 0;
}
void dfs(int ct)
{
    if(sum == k){
        flag = 1;
        return ;
    }
    for(int i=ct; i<n; ++i){
        if(sum+arr[i] <= k)
        {
            vis[i] = 1;
            sum += arr[i];
            dfs(i+1);
            sum -= arr[i];
            vis[i] = 0;
            if(flag)return;
        }
    }
}