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Gray_Code.py
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Gray_Code.py
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```
The gray code is a binary numeral system where two successive values differ in only one bit.
Given a non-negative integer n representing the total number of bits in the code, print the sequence of gray code. A gray code sequence must begin with 0.
For example, given n = 2, return [0,1,3,2]. Its gray code sequence is:
00 - 0
01 - 1
11 - 3
10 - 2
Note:
For a given n, a gray code sequence is not uniquely defined.
For example, [0,2,3,1] is also a valid gray code sequence according to the above definition.
For now, the judge is able to judge based on one instance of gray code sequence. Sorry about that.
```
class Solution:
# @param {integer} n
# @return {integer[]}
def grayCode(self, n):
result = []
for i in xrange(2**n):
result.append(i>>1 ^ i)
return result
def graycode( n):
return [ (i >> 1 ^ i )for i in xrange(1<<n)]
print graycode(3)
#Conver from Gray Code to Normal Code:
def graycode(num):
result = []
for number in num:
mask = number >> 1
while mask != 0:
number = number ^ mask
mask = mask >> 1
result.append(number)
return result
print graycode([0, 1, 3, 2, 6, 7, 5, 4])
#Reference: http://en.wikipedia.org/wiki/Gray_code