[LeetCode] Gray Code

标签：c++   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.

解题思路：

格雷码，相邻两个二进制之间只有一位不同。n位二进制的格雷码的数目是2^n个，且第i个格雷码为(i>>1)^i。估计题目有点问题，当n为0时，应该返回{}，但是这里要求返回{0}

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

[LeetCode] Gray Code

标签：c++   leetcode   

原文地址：http://blog.csdn.net/kangrydotnet/article/details/47275075