### leetcode Question 32: Gary code

Gray Code
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.

Analysis:
See this website about the gray code and the binary to gray algorithm.

Source Code:

class Solution {
public:
unsigned int binary2gray(unsigned int bi){
return (bi>>1)^bi;
}
vector<int> grayCode(int n) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
vector<int> res;
for (unsigned int i=0;i<pow(2,n);i++){
res.push_back(binary2gray(i));
}
return res;
}
};