47.全排列II

class Solution:
    def back(self,nums,used,path,res):
        if len(path) == len(nums):
            res.append(path[:])
            return 
        for i in range(len(nums)):
            if (i >0 and nums[i] == nums[i-1] and not used[i-1]) or used[i]:
                continue
            used[i] = True
            path.append(nums[i])
            self.back(nums,used,path,res)
            used[i] = False
            path.pop()

    def permuteUnique(self, nums: List[int]) -> List[List[int]]:
        nums.sort()
        res = []
        used = [False]*len(nums)
        self.back(nums,used,[],res)
        return res

47. 全排列 II - 力扣（LeetCode）