leetcode刷题，总结，记录，备忘89

leetcode89

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 - 001 - 111 - 310 - 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.

这题真不会做，，，，反正百度了半天，知道了格雷码的规则，就是分为两半部分，下半部分就是讲上半部的挨个反过来加上1即可，最近略忙，有空仔细研究研究。

class Solution {public:    vector<int> grayCode(int n) {        int i,j,count,temp;        vector<int>graycode;        graycode.push_back(0);        for (i=0; i < n; i++)        {            count = graycode.size();            temp = 1 << i;            for (j=count-1; j >= 0; --j)            {                graycode.push_back(graycode[j] + temp);            }        }                return graycode;    }};