Gray Code

最新推荐文章于 2021-02-23 15:28:02 发布

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本文详细介绍了灰码的概念及其生成算法，并提供了一个高效的C++实现方式，通过位运算快速生成指定位数的灰码序列。对于理解灰码原理及在实际应用中使用灰码的开发者具有参考价值。

描述
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:
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.

解法涉及到gray code的数学知识了，要是知道这个数学知识，可以在几分钟之内就解出这道题。
格雷码可以由对应的十进制数求出：grayCode=i^i>>1
runtime:4ms

class Solution {
public:
     vector<int> grayCode(int n) {
         vector<int> result;
         for(int i=0;i<1<<n;i++)//1<<n表示2的n次方。
         {
             result.push_back(i^i>>1);
         }
         return result;
     }

};