// 2205. Gray Code #include using namespace std; static int n; const int max_n = 16; static bool a[max_n + 1]; void print(void) { for (int i = n; i; i--) printf("%d", a[i]); printf("\n"); } int main() { scanf("%d", &n); print(); for (int i = 1; i < 1 << n; i++) { int lsb = __builtin_ffs(i); a[lsb] ^= 1; print(); } }