leetcode-78-Subsets

Given a set of distinct integers, nums, return all possible subsets (the power set).

Note: The solution set must not contain duplicate subsets.

Example:

Input: nums = [1,2,3]
Output:
[
  [3],
  [1],
  [2],
  [1,2,3],
  [1,3],
  [2,3],
  [1,2],
  []
]

class Solution {
    public List<List<Integer>> subsets(int[] nums) {
        Arrays.sort(nums);
        List<List<Integer>> ret = new ArrayList<>();
        dfs(nums, 0, new ArrayList<>(), ret);
        return ret;
    }
    
    void dfs(int[] nums, int idx, List<Integer> path, List<List<Integer>> ret)
    {
        ret.add(path);
        for(int i=idx; i<nums.length; i++)
        {
            List<Integer> p = new ArrayList<>(path);
            p.add(nums[i]);
            dfs(nums, i+1, p, ret);
        }
    }
}