[LeetCode][Python3] 89. Gray Code

Problem :

https://leetcode.com/problems/gray-code/

My Solution :

class Solution:

def grayCode(self, n):

def dfs():

if len(path) == 2**n:

return path[:]

num = path[-1]

visited[num] = 1

for i in range(n):

cand = num ^ 1 << i

if not visited[cand]:

path.append(cand)

ret = dfs()

if ret:

return ret

path.pop()

visited[num] = 0

path = [0]

visited = [0]*(2**n)

return dfs()