题目
Given an integer array nums that may contain duplicates, return all possible subsets (the power set).
The solution set must not contain duplicate subsets. Return the solution in any order.
解题思路
先把所有数排序，从空集开始进行拓展，如果当前的数和上一个相同，只能拓展上一次的结果，否则可以拓展之前所有的结果
代码
class Solution:
def subsetsWithDup(self, nums: List[int]) -> List[List[int]]:
nums.sort()
res = [[], [nums[0]]]
tmp = [[nums[0]]]
for i in range(1, len(nums)):
if nums[i] == nums[i - 1]:
tmp = [t + [nums[i]] for t in tmp]
else:
tmp = [t + [nums[i]] for t in res]
res += tmp
return res
