【LeetCode】78. Subsets

问题描述

Given a set of distinct integers, nums, return all possible subsets.

Note: The solution set must not contain duplicate subsets.

For example,
If nums = [1,2,3], a solution is:

[  [3],  [1],  [2],  [1,2,3],  [1,3],  [2,3],  [1,2],  []]

算法

深度优先，回溯算法

代码

        public List<List<Integer>> subsets(int[] nums) {            List<List<Integer>> res = new ArrayList<>();            dfs(res, new ArrayList<>(), nums, 0);            return res;        }        public void dfs(List<List<Integer>> res, List<Integer> list, int[] nums, int start) {            res.add(new ArrayList<>(list));            for(int i=start;i<nums.length;i++) {                list.add(nums[i]);                dfs(res, list, nums, i+1);                list.remove(list.size()-1);            }        }