Given a set of distinct integers, S, return all possible subsets.
Note:
- Elements in a subset must be in non-descending order.
- The solution set must not contain duplicate subsets.
For example,
If S = [1,2,3]
, a solution is:
[ [3], [1], [2], [1,2,3], [1,3], [2,3], [1,2], [] ]
public ArrayList<ArrayList<Integer>> subsets(int[] S) {
// Note: The Solution object is instantiated only once and is reused by each test case.
Arrays.sort(S);
return subsets(S, 0);
}
public ArrayList<ArrayList<Integer>> subsets(int[] s, int index) {
ArrayList<ArrayList<Integer>> result = new ArrayList<ArrayList<Integer>>();
if(index == s.length) {
result.add(new ArrayList<Integer>());
return result;
}
for(ArrayList<Integer> sub : subsets(s, index + 1)) {
result.add(sub);
ArrayList<Integer> a = new ArrayList<Integer>();
a.add(s[index]);
a.addAll(sub);
result.add(a);
}
return result;
}