subsets-ii.py

'''
Given a collection of integers that might contain duplicates, nums, return all possible subsets (the power set).

Note: The solution set must not contain duplicate subsets.

Example:

Input: [1,2,2]
Output:
[
  [2],
  [1],
  [1,2,2],
  [2,2],
  [1,2],
  []
]


'''


class Solution:
    def subsetsWithDup(self, nums: List[int]) -> List[List[int]]:
        res  = [[]]
        nums.sort()
        for i in range(len(nums)):
            if i == 0 or nums[i] != nums[i-1]:
                l = len(res)
            res += [ res[j] + [nums[i]]   for j in range(len(res)-l, len(res))]
        return res