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.
Example 1:
Input: 2
Output:
[0,1,3,2]
Explanation:
00 - 0
01 - 1
11 - 3
10 - 2
For a given n, a gray code sequence may not be uniquely defined.
For example, [0,2,3,1] is also a valid gray code sequence.
00 - 0
10 - 2
11 - 3
01 - 1Example 2:
Input: 0
Output:
[0]
Explanation: We define the gray code sequence to begin with 0.
A gray code sequence of n has size = 2n, which for n = 0 the size is 20 = 1.
Therefore, for n = 0 the gray code sequence is [0].二进制转成格雷码编码：
class Solution {
public:
vector<int> grayCode(int n) {
vector<int> result;
for(int i=0;i<1<<n;i++)//i<(1左移n位后的结果)
{
result.push_back(i^i>>1);//(i的平方右移1位)
}
return result;
}
};