思路

先转换为二进制数，再用异或性质转换为格雷码~~~
（别问，问就是数电学了这个ha）

code

#include <iostream>
using namespace std;

int n;
unsigned long long int k;

const int N = 70;
int a[N], res[N];
int op(int x, int y)
{
    if (x == y)
        return 0;
    else
        return 1;
}
int main()
{
    cin >> n >> k;
    int i = 1;
    while (k)
    {
        int rem = k % 2;
        a[n + 1 - i] = rem;
        i++;
        k /= 2;
    }
    for (int i = 1; i <= n; i++)
    {
        if (i == 1)
        {
            res[i] = a[i];
        }
        else
        {
            res[i] = op(a[i - 1], a[i]);
        }
    }
    for (int i = 1; i <= n; i++)
    {
        cout << res[i];
    }
    return 0;
}