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.
思路:
二进制-->格雷码:如果二进制码字的第i位和i+1位相同,则对应的格雷码的第i位为0,否则为1。最高为之前可以看作还有一位0,即最高位是和0异或。
*格雷码-->二进制:最左边一位不变,从左边第二位起,将每位与左边一位解码后的值异或,作为该位解码后的值。
class Solution { public: vector<int> grayCode(int n) { vector<int> result; int size = 1 << n; for (int i =0; i< size; i++) { result.push_back(getGrayCode(i)); } return result; } int getGrayCode(int binary) { return ((binary >> 1)^binary); } };