题目：

题解：

class Solution:
    def subsetsWithDup(self, nums: List[int]) -> List[List[int]]:
        if not nums:
            return list()

        results = list()
        nums.sort()
        visited = [False] * len(nums)
        self.dfs(nums, results, list(), visited, 0)
        return results
        
    def dfs(self, nums, results, path, visited, start):
        results.append(list(path))
        
        for i in range(start, len(nums)):
            if visited[i]:
                continue

            if i > 0 and nums[i] == nums[i - 1] and not visited[i - 1]:
                continue

            path.append(nums[i])
            visited[i] = True
            self.dfs(nums, results, path, visited, i + 1)
            path.pop()
            visited[i] = False

        return