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], [] ]
解题思路:
和上题十分相似,修改上题代码即可,JAVA实现如下:
static public List<List<Integer>> subsets(int[] nums) { List<List<Integer>> list = new ArrayList<List<Integer>>(); list.add(new ArrayList<Integer>()); Arrays.sort(nums); for(int i=1;i<=nums.length;i++) dfs(list, nums.length, i, 0,nums,-1); return list; } static List<Integer> alist = new ArrayList<Integer>(); static void dfs(List<List<Integer>> list, int n, int k, int depth,int[] nums,int last) { if (depth >= k) { list.add(new ArrayList<Integer>(alist)); return; } for (int i = last+1; i <= n-k+depth; i++) { alist.add(nums[i]); dfs(list, n, k, depth + 1,nums,i); alist.remove(alist.size() - 1); } }