[LeetCode]Gray 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.

二进制转Gray码的规律就是grayCOde = (binary>>1)^binary。

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