Subsets-LeetCode#78

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],
  []
]

给定一个不同的整数数组 nums[]，返回所有可能的子集（幂集）。
根据77题类似的方法，也是用递归来做

public class Subsets {
    public List<List<Integer>> subsets(int[] nums) {
        List<List<Integer>> res = new ArrayList<>();
        res.add(new ArrayList<>());
        dfs(res, new ArrayList<>(), nums, 0);
        return res;
    }
    public static void dfs(List<List<Integer>> res, List<Integer> temp, int[] nums, int start) {
        if (start == nums.length) {
            return;
        }
        for (int i = start; i < nums.length; i++) {
            temp.add(nums[i]);
            res.add(new ArrayList<>(temp));
            dfs(res, temp, nums, i + 1);
            temp.remove(temp.size() - 1);
        }
    }
    public static void main(String[] args) {
        Subsets subsets = new Subsets();
        int[] nums = {1, 2, 3};
        subsets.subsets(nums);
    }
}