from typing import List class Solution: def permuteUnique(self, nums: List[int]) -> List[List[int]]: ans = [] option = [0] * len(nums) elements = {} for n in nums: if n in elements: elements[n] += 1 else: elements[n] = 1 def dfs(idx: int): for k, v in elements.items(): if v > 0: option[idx] = k elements[k] -= 1 if idx == len(nums) - 1: ans.append(option.copy()) else: dfs(idx + 1) elements[k] += 1 dfs(0) return ans