ref general-solving/leetcode/0078_subsets.cs

0078_subsets.cs

// for leetcode meetup
// O(2^n), O(2^n)
public IList<IList<int>> Subsets(int[] nums, int index = nums.Length) {
  if (index == 0)
    return new List<IList<int>>(new IList<int>[] { new List<int>() });

  var temp = Subsets(nums, index - 1);
  int tempLength = temp.Count;

  for (int i = 0; i < tempLength; i++) {
    temp.Add(new List<int>(temp[i]));
    temp[temp.Count - 1].Add(nums[index - 1]);
  }
  return temp;
}