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  1. #include <iostream>
  2. #include <vector>
  3. using namespace std;
  4. #pragma warning (disable: 4996)
  5.  
  6. long long N, X; bool used[1 << 19];
  7. vector<long long>E;
  8.  
  9. int main() {
  10. 	cin >> N >> X;
  11. 	if (X >= (1LL << N)) {
  12. 		for (int i = 0; i < (1 << N); i++) E.push_back(i);
  13. 	}
  14. 	else {
  15. 		for (int i = 0; i < (1 << N); i++) {
  16. 			if (used[i] == true) continue;
  17. 			E.push_back(i);
  18. 			used[i] = true; used[i^X] = true;
  19. 		}
  20. 	}
  21.  
  22. 	cout << (int)E.size() - 1 << endl;
  23. 	for (int i = 0; i < (int)E.size() - 1; i++) { if (i) printf(" "); printf("%d", (E[i + 1] ^ E[i])); } printf("\n");
  24. 	return 0;
  25. }
Success #stdin #stdout 0s 15752KB
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stdin
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3 7
stdout
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3
1 3 1
https://ideone.com/57OHBa
language:
C++14 (gcc 8.3)
created:
5 years ago
visibility:
public

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