题解 | #有重复项数字的全排列#

class Solution:
    def permuteUnique(self , num: List[int]) -> List[List[int]]:
        # write code here
        res = []
        path = []
        n = len(num)

        def backtrack(array, n):
            if len(path) == n and path[:] not in res:
                res.append(path[:])
                return 
            
            for i, val in enumerate(array):
                path.append(val)
                del array[i]

                backtrack(array, n)

                array.insert(i, val)

                path.pop()

        backtrack(num, n)
        res.sort()
        return res