leetcode78. 子集

class Solution {
    



    List> ans = new ArrayList<>();
    List path = new ArrayList<>();

    public void getAns(int[] nums,int st) {
        ans.add(new ArrayList<>(path));//放到首位 可以将空添加进去

        for (int i = st; i < nums.length; i++) {
            path.add(nums[i]);
            getAns(nums,i+1);
            path.remove(path.size()-1);
        }

    }


    public List> subsets(int[] nums) {
        getAns(nums,0);
        return ans;
    }
}