#![allow(unused_imports, unused_macros, dead_code)] use std::{cmp::*, collections::*}; fn main() { let mut sc = Scanner::new(); let n: usize = sc.cin(); let k: i64 = sc.cin(); let xs: Vec = sc.vec(n); let s = mint!(xs.iter().sum()); let ans = s * mint!(2).pow(k); put!(ans); } // @algebra/modint #[derive(Debug, PartialEq, Eq, Clone, Copy)] pub struct ModInt(pub i64, pub i64); // (residual, modulo) pub const MOD_1000000007: i64 = 1_000_000_007; pub const MOD_998244353: i64 = 998_244_353; impl ModInt { pub fn new(residual: i64, modulo: i64) -> ModInt { if residual >= modulo { ModInt(residual % modulo, modulo) } else if residual < 0 { ModInt((residual % modulo) + modulo, modulo) } else { ModInt(residual, modulo) } } pub fn unwrap(self) -> i64 { self.0 } pub fn inv(self) -> Self { fn exgcd(r0: i64, a0: i64, b0: i64, r: i64, a: i64, b: i64) -> (i64, i64, i64) { if r > 0 { exgcd(r, a, b, r0 % r, a0 - r0 / r * a, b0 - r0 / r * b) } else { (a0, b0, r0) } } let (a, _, r) = exgcd(self.0, 1, 0, self.1, 0, 1); if r != 1 { panic!("{:?} has no inverse!", self); } ModInt(((a % self.1) + self.1) % self.1, self.1) } pub fn pow(self, n: i64) -> Self { if n < 0 { self.pow(-n).inv() } else if n == 0 { ModInt(1, self.1) } else if n == 1 { self } else { let mut x = (self * self).pow(n / 2); if n % 2 == 1 { x *= self } x } } } impl std::fmt::Display for ModInt { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { write!(f, "{}", self.0) } } impl std::ops::Neg for ModInt { type Output = Self; fn neg(self) -> Self { if self.0 == 0 { return self; } ModInt(self.1 - self.0, self.1) } } impl std::ops::Add for ModInt { type Output = Self; fn add(self, other: i64) -> Self { ModInt::new(self.0 + other, self.1) } } impl std::ops::Add for ModInt { type Output = Self; fn add(self, other: ModInt) -> Self { self + other.0 } } impl std::ops::Add for i64 { type Output = ModInt; fn add(self, other: ModInt) -> ModInt { other + self } } impl std::ops::AddAssign for ModInt { fn add_assign(&mut self, other: i64) { self.0 = ModInt::new(self.0 + other, self.1).0; } } impl std::ops::AddAssign for ModInt { fn add_assign(&mut self, other: ModInt) { *self += other.0; } } impl std::ops::Sub for ModInt { type Output = Self; fn sub(self, other: i64) -> Self { ModInt::new(self.0 - other, self.1) } } impl std::ops::Sub for ModInt { type Output = Self; fn sub(self, other: ModInt) -> Self { self - other.0 } } impl std::ops::Sub for i64 { type Output = ModInt; fn sub(self, other: ModInt) -> ModInt { ModInt::new(self - other.0, other.1) } } impl std::ops::SubAssign for ModInt { fn sub_assign(&mut self, other: i64) { self.0 = ModInt::new(self.0 - other, self.1).0; } } impl std::ops::SubAssign for ModInt { fn sub_assign(&mut self, other: ModInt) { *self -= other.0; } } impl std::ops::Mul for ModInt { type Output = Self; fn mul(self, other: i64) -> Self { ModInt::new(self.0 * other, self.1) } } impl std::ops::Mul for ModInt { type Output = Self; fn mul(self, other: ModInt) -> Self { self * other.0 } } impl std::ops::Mul for i64 { type Output = ModInt; fn mul(self, other: ModInt) -> ModInt { other * self } } impl std::ops::MulAssign for ModInt { fn mul_assign(&mut self, other: i64) { self.0 = ModInt::new(self.0 * other, self.1).0; } } impl std::ops::MulAssign for ModInt { fn mul_assign(&mut self, other: ModInt) { *self *= other.0; } } impl std::ops::Div for ModInt { type Output = Self; fn div(self, other: ModInt) -> Self { self * other.inv() } } impl std::ops::Div for ModInt { type Output = Self; fn div(self, other: i64) -> Self { self / ModInt::new(other, self.1) } } impl std::ops::Div for i64 { type Output = ModInt; fn div(self, other: ModInt) -> ModInt { other.inv() * self } } impl std::ops::DivAssign for ModInt { fn div_assign(&mut self, other: ModInt) { self.0 = (*self / other).0; } } impl std::ops::DivAssign for ModInt { fn div_assign(&mut self, other: i64) { *self /= ModInt(other, self.1); } } #[macro_export] macro_rules! mint { ($x:expr) => { ModInt::new($x, MOD_998244353) }; } impl std::iter::Sum for ModInt { fn sum(iter: I) -> Self where I: Iterator, { let mut r = mint!(0); for x in iter { r = r + x } r } } // {{{ use std::io::{self, Write}; use std::str::FromStr; struct Scanner { stdin: io::Stdin, buffer: VecDeque, } impl Scanner { fn new() -> Self { Self { stdin: io::stdin(), buffer: VecDeque::new(), } } fn cin(&mut self) -> T { while self.buffer.is_empty() { let mut line = String::new(); let _ = self.stdin.read_line(&mut line); for w in line.split_whitespace() { self.buffer.push_back(String::from(w)); } } self.buffer.pop_front().unwrap().parse::().ok().unwrap() } fn chars(&mut self) -> Vec { self.cin::().chars().collect() } fn vec(&mut self, n: usize) -> Vec { (0..n).map(|_| self.cin()).collect() } } fn flush() { std::io::stdout().flush().unwrap(); } #[macro_export] macro_rules! min { (.. $x:expr) => {{ let mut it = $x.iter(); it.next().map(|z| it.fold(z, |x, y| min!(x, y))) }}; ($x:expr) => ($x); ($x:expr, $($ys:expr),*) => {{ let t = min!($($ys),*); if $x < t { $x } else { t } }} } #[macro_export] macro_rules! max { (.. $x:expr) => {{ let mut it = $x.iter(); it.next().map(|z| it.fold(z, |x, y| max!(x, y))) }}; ($x:expr) => ($x); ($x:expr, $($ys:expr),*) => {{ let t = max!($($ys),*); if $x > t { $x } else { t } }} } #[macro_export] macro_rules! trace { ($x:expr) => { #[cfg(debug_assertions)] eprintln!(">>> {} = {:?}", stringify!($x), $x) }; ($($xs:expr),*) => { trace!(($($xs),*)) } } #[macro_export] macro_rules! put { (.. $x:expr) => {{ let mut it = $x.iter(); if let Some(x) = it.next() { print!("{}", x); } for x in it { print!(" {}", x); } println!(""); }}; ($x:expr) => { println!("{}", $x) }; ($x:expr, $($xs:expr),*) => { print!("{} ", $x); put!($($xs),*) } } // }}}