#include #define FASTIO using namespace std; using ll = long long; using Vi = std::vector; using Vl = std::vector; using Pii = std::pair; using Pll = std::pair; constexpr int I_INF = std::numeric_limits::max(); constexpr ll L_INF = std::numeric_limits::max(); template inline bool chmin(T1& a, const T2& b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T1& a, const T2& b) { if (a < b) { a = b; return true; } return false; } template class Prints { private: class __Prints { public: __Prints(const char* sep, const char* term) : sep(sep), term(term) {} template auto operator()(const Args&... args) const -> decltype((os << ... << std::declval()), void()) { print(args...); } template auto pvec(const T& vec, size_t sz) const -> decltype(os << std::declval()[0])>(), void()) { for (size_t i = 0; i < sz; i++) os << vec[i] << (i == sz - 1 ? term : sep); } template auto pmat(const T& mat, size_t h, size_t w) -> decltype(os << std::declval()[0][0])>(), void()) { for (size_t i = 0; i < h; i++) for (size_t j = 0; j < w; j++) os << mat[i][j] << (j == w - 1 ? term : sep); } private: const char *sep, *term; void print() const { os << term; } void print_rest() const { os << term; } template void print(const T& head, const Tail&... tail) const { os << head, print_rest(tail...); } template void print_rest(const T& head, const Tail&... tail) const { os << sep << head, print_rest(tail...); } }; public: Prints() {} __Prints operator()(const char* sep = " ", const char* term = "\n") const { return __Prints(sep, term); } }; Prints<> prints; Prints prints_err; //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% template class ModInt { using i64 = std::int_fast64_t; private: i64 m_value; public: constexpr ModInt(const i64 x = 0) noexcept : m_value(x) { if (m_value < -Modulus || m_value >= Modulus) m_value %= Modulus; if (m_value < 0) m_value += Modulus; } constexpr i64 const& value() const noexcept { return m_value; } constexpr ModInt& operator+=(const ModInt rhs) noexcept { m_value += rhs.m_value; if (m_value >= Modulus) { m_value -= Modulus; } return *this; } constexpr ModInt& operator-=(const ModInt rhs) noexcept { if (m_value < rhs.m_value) { m_value += Modulus; } m_value -= rhs.m_value; return *this; } constexpr ModInt& operator*=(const ModInt rhs) noexcept { m_value *= rhs.m_value; if (m_value >= Modulus) m_value %= Modulus; return *this; } constexpr ModInt& operator/=(ModInt rhs) noexcept { *this *= rhs.inv(); return *this; } constexpr ModInt& operator++() noexcept { *this += 1; return *this; } constexpr ModInt operator++(int) noexcept { ModInt res = *this; *this += 1; return res; } constexpr ModInt& operator--() noexcept { *this -= 1; return *this; } constexpr ModInt operator--(int) noexcept { ModInt res = *this; *this -= 1; return res; } constexpr ModInt inv() const noexcept { i64 q = m_value; i64 b = Modulus, u = 1, v = 0; i64 tmp = 0; while (b) { i64 t = q / b; q -= t * b; tmp = q, q = b, b = tmp; u -= t * v; tmp = u, u = v, v = tmp; } if (u < -Modulus || u >= Modulus) u %= Modulus; if (u < 0) u += Modulus; return u; } constexpr ModInt pow(i64 k) const noexcept { ModInt res = 1; ModInt tmp = 0; if (k < 0) { tmp = this->inv(); k = -k; } else { tmp = *this; } for (; k > 0; k >>= 1) { if (k & 1) res *= tmp; tmp *= tmp; } return res; } friend constexpr ModInt operator+(const ModInt& a) noexcept { return a; } friend constexpr ModInt operator-(const ModInt& a) noexcept { return ModInt(0) - a; } friend constexpr ModInt operator+(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) += rhs; } friend constexpr ModInt operator-(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) -= rhs; } friend constexpr ModInt operator*(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) *= rhs; } friend constexpr ModInt operator/(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) /= rhs; } friend constexpr bool operator<(const ModInt& lhs, const ModInt& rhs) noexcept { return lhs.m_value < rhs.m_value; } friend constexpr bool operator>(const ModInt& lhs, const ModInt& rhs) noexcept { return lhs.m_value > rhs.m_value; } friend constexpr bool operator<=(const ModInt& lhs, const ModInt& rhs) noexcept { return lhs.m_value <= rhs.m_value; } friend constexpr bool operator>=(const ModInt& lhs, const ModInt& rhs) noexcept { return lhs.m_value >= rhs.m_value; } friend constexpr bool operator==(const ModInt& lhs, const ModInt& rhs) noexcept { return lhs.m_value == rhs.m_value; } friend constexpr bool operator!=(const ModInt& lhs, const ModInt& rhs) noexcept { return lhs.m_value != rhs.m_value; } friend std::istream& operator>>(std::istream& is, ModInt& rhs) { i64 a; is >> a; rhs = a; return is; } friend std::ostream& operator<<(std::ostream& os, const ModInt& rhs) { os << rhs.m_value; return os; } }; constexpr long long MOD = 998244353; using Mint = ModInt; void solve() { ll N, K; cin >> N >> K; vector A(N); for (ll i = 0; i < N; i++) { cin >> A[i]; } Mint sum = accumulate(A.begin(), A.end(), Mint(0)); Mint y = (Mint(2).pow(K) - 1) / N; Mint ans = sum * (y * N + 1); prints()(ans); } //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% int main() { #ifdef FASTIO std::cin.tie(nullptr), std::cout.tie(nullptr); std::ios::sync_with_stdio(false); #endif #ifdef FILEINPUT std::ifstream ifs("./in_out/input.txt"); std::cin.rdbuf(ifs.rdbuf()); #endif #ifdef FILEOUTPUT std::ofstream ofs("./in_out/output.txt"); std::cout.rdbuf(ofs.rdbuf()); #endif std::cout << std::setprecision(18) << std::fixed; solve(); std::cout << std::flush; return 0; }