Subsets —— LeetCode

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

Note:

• Elements in a subset must be in non-descending order.
• 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],

  []

]

 

题目大意：给定一个没有重复元素的数组，输出所有子集。

解题思路：直接看代码。

public class Solution {

    public List<List<Integer>> subsets(int[] nums) {

        List<List<Integer>> res = new ArrayList<>();

        if(nums == null){

            return res;

        }

        Arrays.sort(nums);

        res.add(new ArrayList<>());

        for(int i=0;i<nums.length;i++){

            int currSize = res.size();

            for(int j=0;j<currSize;j++){

                List<Integer> tmp = new ArrayList<>(res.get(j));

                tmp.add(nums[i]);

                res.add(tmp);

            }

        }

        return res;

    }

}