题目：

题解：

func subsets(nums []int) (ans [][]int) {set := []int{}var dfs func(int)dfs = func(cur int) {if cur == len(nums) {ans = append(ans, append([]int(nil), set...))return}set = append(set, nums[cur])dfs(cur + 1)set = set[:len(set)-1]dfs(cur + 1)}dfs(0)return
}