89. 格雷编码

为保证权益，题目请参考 89. 格雷编码(From LeetCode).

解决方案1

CPP

#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

class Solution
{
public:
    vector<int> grayCode(int n)
    {
        vector<int> ans(pow(2, n), 0);

        ans[0] = 0;
        ans[1] = 1;
        for (int i = 1; i < n; i++)
        {
            for (int j = pow(2, i); j < pow(2, i + 1); j++)
            {
                ans[j] = (1 << i) + ans[pow(2, i) - (j - pow(2, i)) - 1];
            }
        }
        return ans;
    }
};

int main()
{
    Solution so;
    for (auto x : so.grayCode(4))
    {
        cout << x << endl;
    }
    return 0;
}

Python

# 89. 格雷编码
# https://leetcode-cn.com/problems/gray-code/

from typing import List


class Solution:
    def grayCode(self, n: int) -> List[int]:
        ans = [0]
        for i in range(n):
            t = len(ans)
            for j in range(t - 1, -1, -1):
                ans.append(ans[j] ^ (1 << i))
        return ans


if __name__ == "__main__":
    solution = Solution()
    print(solution.grayCode(2))