Leetcode: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.

给定位数的格雷码。思路：自然二进制码转换成二进制格雷码，其法则是保留自然二进制码的最高位作为格雷码的最高位，而次高位格雷码为二进制码的高位与次高位相异或，而格雷码其余各位与次高位的求法相类似。

实现代码：

class Solution {
public:
vector<int> grayCode(int n) {
vector<int> result;
int nSize = 1 << n;
for (int i = 0; i < nSize; ++i)
{
result.push_back((i>>1)^i);
}
return result;
}
};