leetcode Combinations

public class Solution {
int n;
int k;
//boolean record[];
LinkedList<List<Integer>>result;
LinkedList<Integer>temp;
public List<List<Integer>> combine(int n, int k) {
this.n=n;
this.k=k;

result=new LinkedList<List<Integer>>();
temp=new LinkedList<Integer>();
help(0,1);

return result;
}

void help(int step,int starIndex)
{
if(step==k)
{
result.add(new LinkedList<Integer>(temp));
return;
}
for(int i=starIndex;i<=n;i++)
{
temp.add(i);
help(step+1,i+1);
temp.removeLast();
}
}
}