题目

代码

class Solution {
    List< List<Integer> > result = new ArrayList<>();
    LinkedList<Integer> path = new LinkedList<>();
    public List<List<Integer>> subsets(int[] nums) {
        backtracking(nums,0);
        return result;
    }
    public void backtracking(int [] nums,int startIndex ) {
        result.add(new ArrayList<>(path));
        for(int i = startIndex; i < nums.length; i++ ) {
            path.add(nums[i]);
            backtracking(nums,i +1 );
            path.removeLast();
        }
    }
}