Language: C++

#include <iostream>
#include <fstream>
#include <vector>
#include <deque>
#include <set>
#include <map>
#include <unordered_map>
#include <list>
#include <array>
#include <cstdlib>
#include <stack>
#include <string>
#include <queue>
#include <chrono>
#include <functional>
#include <limits>
#include <cmath>
#include <algorithm>
#include <random>
#include <regex>
#include <tuple>
#include <utility>
#include <bitset>
#include <complex>
#include <iomanip>
#include <ostream>
#include <sstream>
#include <ctime>
using namespace std;
#define for0(i, n) for(int i = 0; i < n; i++)
#define for1(i, n) for(int i = 1; i <= n; i++)
#define pb push_back
#define mp make_pair
#define all(v) v.begin(), v.end()
#define V vector<int>
#define VP vector<pair<int, int> >
#define FASTIO ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define index INDEX
#ifndef ONLINE_JUDGE
#define print(x) PRINT(x, #x)
template<typename T> inline const void PRINT(T VARIABLE, const string& NAME) {
	cerr << NAME << " = " << fixed << VARIABLE << "\n";
}
#else
#define print(x) 0 
#endif
#ifdef RAND_MAX
#undef RAND_MAX
#endif
#define RAND_MAX 999999937 
int generate_random() {
	const int MAX_RANDOM = (int)1e6;
	mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
	return uniform_int_distribution<int>(0, MAX_RANDOM)(rng);
}
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
const ll INFLL = 2 * (ll)1e18 + 100;
#define int ll
#ifdef int 
const int INFINT = INFLL;
#else
const int INFINT = 2 * (int)1e9 + 100;
#endif
const double PI = atan(1) * 4;
const double EPS = 1e-6;
const int SEED = (int)1e3 + 7;
const int MOD = (int)1e9 + 7;
const int NMAX = (int)1e6 + 5;

void check(int n, int k)
{
	V v;
	for0(i, (1 << n)) v.pb(i), v.pb(i);
	do
	{
		for0(i, (1 << n))
		{
			int start = -1, finish = -1;
			for0(j, v.size())
			{
				auto it = v[j];
				if (it == i)
				{
					if (start == -1) start = j;
					else
					{
						finish = j;
						break;
					}
				}
			}
			int xor_here = 0;
			for (int j = start; j <= finish; j++) xor_here ^= v[j];
			if (xor_here != k) goto skip;
		}
		cout << "GOT ANS for " << n << ' ' << k << '\n';
		for (auto i : v) cout << i << ' ';
		cout << "\n\n";
		break;
	skip:;
	} while (next_permutation(all(v)));
}
#define xor XOR
int32_t main() {
#ifndef ONLINE_JUDGE
	double START_PROGRAM = clock();
#endif
	srand(time(0));
	cout << setprecision(20) << fixed;
	FASTIO;
	int n, k;
	cin >> n >> k;
	if(k == 0)
	{
		for0(i, (1 << n)) cout << i << ' ' << i << ' ';
		return 0;
	}
	int xor = 0;
	for0(i, (1 << n)) if(i != k) xor ^= i;
	if(xor == k)
	{
		for (int j = (1 << n) - 1; j >= 0; j--) if (j != k) cout << j << ' ';
		cout << k << ' ';
		for0(j, (1 << n)) if (j != k) cout << j << ' ';
		cout << k << ' ';
	}
	else cout << -1;






#ifndef ONLINE_JUDGE
	double END_PROGRAM = clock();
	double ELAPSED_TIME = (END_PROGRAM - START_PROGRAM) / CLOCKS_PER_SEC;
	cerr << "\n\nElapsed Time: " << ELAPSED_TIME * 1000 << "\n";
	system("pause");
#endif
	return 0;
}







Compiler output:
a.cc:105:9: error: "xor" cannot be used as a macro name as it is an operator in C++
  105 | #define xor XOR
      |         ^~~
a.cc: In function 'int32_t main()':
a.cc:120:13: error: expected unqualified-id before 'xor' token
  120 |         int xor = 0;
      |             ^~~
a.cc:121:38: error: expected primary-expression before 'xor' token
  121 |         for0(i, (1 << n)) if(i != k) xor ^= i;
      |                                      ^~~
a.cc:121:42: error: expected primary-expression before '^=' token
  121 |         for0(i, (1 << n)) if(i != k) xor ^= i;
      |                                          ^~
a.cc:122:12: error: expected primary-expression before 'xor' token
  122 |         if(xor == k)
      |            ^~~
a.cc:122:16: error: expected primary-expression before '==' token
  122 |         if(xor == k)
      |                ^~