题解 | 有重复项数字的全排列

#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param num int整型一维数组 
# @return int整型二维数组
#
class Solution:
    def permuteUnique(self , num: List[int]) -> List[List[int]]:
        # write code here

        sorted_list = sorted(num)
        result_list = []
        path = []
        used = [False] * len(num)

        def backtrack():
            if len(path) == len(sorted_list):
                result_list.append(path.copy())
                return
            for i in range(len(sorted_list)):
                if used[i]:
                    continue
                path.append(sorted_list[i])
                used[i] = True
                backtrack()

                path.pop()
                used[i] = False
        
        backtrack()
        unique_list = [list(t) for t in set(tuple(lst) for lst in result_list)]
        return sorted(unique_list)