Gray Code Leetcode Solution

In this post, we are going to solve the Gray Code Leetcode Solution problem of Leetcode. This Leetcode problem is done in many programming languages like C++, Java, and Python.

Problem

An n-bit gray code sequence is a sequence of `2n` integers where:

• Every integer is in the inclusive range `[0, 2n - 1]`,
• The first integer is `0`,
• An integer appears no more than once in the sequence,
• The binary representation of every pair of adjacent integers differs by exactly one bit, and
• The binary representation of the first and last integers differs by exactly one bit.

Given an integer `n`, return any valid n-bit gray code sequence.

Example 1:

```Input: n = 2
Output: [0,1,3,2]
Explanation:
The binary representation of [0,1,3,2] is [00,01,11,10].
- 00 and 01 differ by one bit
- 01 and 11 differ by one bit
- 11 and 10 differ by one bit
- 10 and 00 differ by one bit
[0,2,3,1] is also a valid gray code sequence, whose binary representation is [00,10,11,01].
- 00 and 10 differ by one bit
- 10 and 11 differ by one bit
- 11 and 01 differ by one bit
- 01 and 00 differ by one bit
```

Example 2:

```Input: n = 1
Output: [0,1]
```

Constraints:

• `1 <= n <= 16`

Now, lets see the leetcode solution of Gray Code Leetcode Solution.

Gray CodeLeetcode Solution in Python

```class Solution:
def grayCode(self, n: int) -> List[int]:
ans = [0]

for i in range(n):
for j in reversed(range(len(ans))):
ans.append(ans[j] | 1 << i)

return ans
```

Gray Code Leetcode Solutionin CPP

```class Solution {
public:
vector<int> grayCode(int n) {
vector<int> ans{0};

for (int i = 0; i < n; ++i)
for (int j = ans.size() - 1; j >= 0; --j)
ans.push_back(ans[j] | 1 << i);

return ans;
}
};
```

Gray Code Leetcode Solution in Java

```class Solution {
public List<Integer> grayCode(int n) {
List<Integer> ans = new ArrayList<>();