[LeetCode][Python3] 47. Permutations II

Problem :

https://leetcode.com/problems/permutations-ii/

My Solution :

class Solution:

def permuteUnique(self, nums):

def backtrack():

if len(path) == len(nums):

ret.append(path[:])

else:

for n in counter:

if counter[n]:

path.append(n)

counter[n] -= 1

backtrack()

path.pop()

counter[n] += 1

counter = {}

for n in nums:

counter[n] = counter.get(n, 0) + 1

path, ret = [], []

backtrack()

return ret