Title Description:
Gray code is a binary number system, in this system, only two successive values of a difference in number of bits.
Given a total number of bits representing an encoded non-negative integer n, which is the print gray coding sequence. Gray coding sequence must begin with 0.
Example 1:
Input: 2
Output: [0,1,3,2]
Explanation:
00 - 0
01 -. 1
. 11 -. 3
10 - 2
For a given n, which is not unique Golay coding sequence.
For example, [0,2,3,1] Gray coding is also a valid sequence.
00 - 0
10 - 2
11 - 3
01 - 1
Example 2:
Input: 0
Output: [0]
Explanation: We define Golay coding sequence must start with 0.
The total number of bits to encode a given Golay coding sequence of n, has a length of 2n. When n = 0, length 20 = 1.
Thus, when n = 0, which is a Gray code sequence [0].
Source: stay button (LeetCode)
link: https: //leetcode-cn.com/problems/gray-code
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answer:
/**
* Note: The returned array must be malloced, assume caller calls free().
*/
int* grayCode(int n, int* returnSize)
{
int len = 0;
int i = 0;
len = 1 << n;
int *a = malloc(sizeof(int)*len);
for(i = 0;i<len;i++)
{
a[i] = i^(i>>1);
}
*returnSize = len;
return a;
}
Operating results :
