78 Subsets
public class Solution { public ArrayList<ArrayList<Integer>> subsets(int[] nums) { ArrayList<ArrayList<Integer>> res = new ArrayList<ArrayList<Integer>>(); ArrayList<Integer> list = new ArrayList<Integer>(); if (nums == null || nums.length == 0) { return res; } Arrays.sort(nums); dfs(nums, 0, res, list); return res; } public void dfs(int[] nums, int start, ArrayList<ArrayList<Integer>> res, ArrayList<Integer> list) { res.add(new ArrayList<Integer>(list)); for (int i = start; i < nums.length; i++) { list.add(nums[i]); dfs(nums, i+1, res, list); list.remove(list.size() - 1); } } }