[LeetCode]78 Subsets

public class Solution {
public List<List<Integer>> subsets(int[] S) {

Arrays.sort(S);

List<List<Integer>> results = new ArrayList<>();
help(S, 0, new ArrayList<Integer>(), results);
return results;
}

private void help(int[] S, int start, List<Integer> items, List<List<Integer>> results)
{
if (items.size() <= S.length)
{
results.add(new ArrayList<Integer>(items));
}

if (items.size() == S.length)
return;

for (int i = start ; i < S.length ; i ++)
{
items.add(S[i]);

help(S, i + 1, items, results);

items.remove(items.size() - 1);
}
}
}