題目：

題解：

func subsetsWithDup(nums []int) (ans [][]int) {sort.Ints(nums)n := len(nums)
outer:for mask := 0; mask < 1<<n; mask++ {t := []int{}for i, v := range nums {if mask>>i&1 > 0 {if i > 0 && mask>>(i-1)&1 == 0 && v == nums[i-1] {continue outer}t = append(t, v)}}ans = append(ans, append([]int(nil), t...))}return
}