class Solution {//题解思路//LinkedList<Integer> path = new LinkedList<>(); List<List<Integer>> results = new ArrayList<>();public List<List<Integer>> subsets(int[] nums) {//主方法中调用方法同时传入指定的参数初始值backTrack(nums, 0);return results;}public void backTrack(int[] nums, int startIndex) {results.add(new ArrayList<>(path));if (startIndex >= nums.length) {return;}for (int i = startIndex; i < nums.length; i++) {path.add(nums[i]);backTrack(nums, i +1);path.removeLast();}}
}