#![allow(unused_imports, unused_macros)] use kyoproio::*; use std::{ collections::*, io::{self, prelude::*}, iter, mem::{replace, swap}, }; fn run(mut kin: I, mut out: O) { macro_rules! output { ($($args:expr),+) => { write!(&mut out, $($args),+).unwrap(); }; } macro_rules! outputln { ($($args:expr),+) => { output!($($args),+); outputln!(); }; () => { output!("\n"); if cfg!(debug_assertions) { out.flush().unwrap(); } } } let (n, k): (usize, i64) = kin.input(); let s = kin.iter::().take(n).map(|x| mint(x)).sum::(); let k = (k % (Mod998244353::modulo() - 1) as i64) as i32; let ans = s * mint(2).pow(k); outputln!("{}", ans); } type Mint = ModInt; pub fn mint>(x: T) -> ModInt { ModInt::new(x.into()) } pub trait Modulo: Copy { fn modulo() -> i32; } macro_rules! modulo_impl { ($($Type:ident $val:tt)*) => { $(#[derive(Copy, Clone, Eq, PartialEq, Default)] pub struct $Type; impl Modulo for $Type { fn modulo() -> i32 { $val } })* }; } modulo_impl!(Mod998244353 998244353 Mod1e9p7 1000000007); use std::sync::atomic; #[derive(Copy, Clone, Eq, PartialEq, Default)] pub struct VarMod; static VAR_MOD: atomic::AtomicI32 = atomic::AtomicI32::new(0); pub fn set_var_mod(m: i32) { VAR_MOD.store(m, atomic::Ordering::Relaxed); } impl Modulo for VarMod { fn modulo() -> i32 { VAR_MOD.load(atomic::Ordering::Relaxed) } } use std::{fmt, marker::PhantomData, ops}; #[derive(Copy, Clone, Eq, PartialEq)] pub struct ModInt(i32, PhantomData); impl ModInt { pub fn new(x: i32) -> Self { debug_assert!(x < M::modulo()); Self(x, PhantomData) } pub fn normalize(self) -> Self { if 0 <= self.0 && self.0 < self.m() { self } else { Self::new(self.0.rem_euclid(self.m())) } } pub fn get(self) -> i32 { self.0 } pub fn inv(self) -> Self { self.pow(self.m() - 2) } pub fn pow(self, mut n: i32) -> Self { while n < 0 { n += self.m() - 1; } let mut x = self; let mut y = Self::new(1); while n > 0 { if n % 2 == 1 { y *= x; } x *= x; n /= 2; } y } pub fn half(self) -> Self { Self::new(self.0 / 2 + self.0 % 2 * ((self.m() + 1) / 2)) } fn m(self) -> i32 { M::modulo() } } impl ops::Neg for ModInt { type Output = Self; fn neg(self) -> Self { Self::new(if self.0 == 0 { 0 } else { self.m() - self.0 }) } } impl ops::AddAssign for ModInt { fn add_assign(&mut self, rhs: Self) { self.0 += rhs.0; if self.0 >= self.m() { self.0 -= self.m(); } } } impl ops::SubAssign for ModInt { fn sub_assign(&mut self, rhs: Self) { self.0 -= rhs.0; if self.0 < 0 { self.0 += self.m(); } } } impl ops::MulAssign for ModInt { fn mul_assign(&mut self, rhs: Self) { self.0 = (self.0 as u32 as u64 * rhs.0 as u32 as u64 % self.m() as u32 as u64) as i32; } } impl ops::DivAssign for ModInt { fn div_assign(&mut self, rhs: Self) { assert_ne!(rhs.0, 0); *self *= rhs.inv(); } } macro_rules! op_impl { ($($Op:ident $op:ident $OpAssign:ident $op_assign:ident)*) => { $(impl ops::$Op for ModInt { type Output = Self; fn $op(self, rhs: Self) -> Self { let mut res = self; ops::$OpAssign::$op_assign(&mut res, rhs); res } })* }; } op_impl! { Add add AddAssign add_assign Sub sub SubAssign sub_assign Mul mul MulAssign mul_assign Div div DivAssign div_assign } impl std::iter::Sum for ModInt { fn sum>(iter: I) -> Self { iter.fold(ModInt::new(0), |x, y| x + y) } } impl std::iter::Product for ModInt { fn product>(iter: I) -> Self { iter.fold(ModInt::new(1), |x, y| x * y) } } impl fmt::Display for ModInt { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { self.0.fmt(f) } } impl fmt::Debug for ModInt { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.pad("ModInt(")?; self.0.fmt(f)?; f.pad(")") } } // ----------------------------------------------------------------------------- fn main() -> io::Result<()> { std::thread::Builder::new() .stack_size(64 * 1024 * 1024) .spawn(|| { run( KInput::new(io::stdin()), io::BufWriter::new(io::stdout().lock()), ) })? .join() .unwrap(); Ok(()) } // ----------------------------------------------------------------------------- pub mod kyoproio { use std::{io::prelude::*, mem}; pub trait Input { fn bytes(&mut self) -> &[u8]; fn str(&mut self) -> &str { std::str::from_utf8(self.bytes()).unwrap() } fn input(&mut self) -> T { T::input(self) } fn iter(&mut self) -> Iter { Iter(self, std::marker::PhantomData) } fn seq>(&mut self, n: usize) -> B { self.iter().take(n).collect() } } pub struct KInput { src: R, buf: Vec, pos: usize, len: usize, } impl KInput { pub fn new(src: R) -> Self { Self { src, buf: vec![0; 1 << 16], pos: 0, len: 0, } } } impl Input for KInput { fn bytes(&mut self) -> &[u8] { loop { while let Some(delim) = self.buf[self.pos..self.len] .iter() .position(|b| b.is_ascii_whitespace()) { let p = self.pos; self.pos += delim + 1; if delim > 0 { return &self.buf[p..p + delim]; } } if self.read() == 0 { return &self.buf[mem::replace(&mut self.pos, self.len)..self.len]; } } } } impl KInput { fn read(&mut self) -> usize { if self.pos > 0 { self.buf.copy_within(self.pos..self.len, 0); self.len -= self.pos; self.pos = 0; } else if self.len >= self.buf.len() { self.buf.resize(2 * self.buf.len(), 0); } let read = self.src.read(&mut self.buf[self.len..]).unwrap(); self.len += read; read } } pub struct Iter<'a, T, I: ?Sized>(&'a mut I, std::marker::PhantomData<*const T>); impl<'a, T: InputParse, I: Input + ?Sized> Iterator for Iter<'a, T, I> { type Item = T; fn next(&mut self) -> Option { Some(self.0.input()) } fn size_hint(&self) -> (usize, Option) { (!0, None) } } pub trait InputParse: Sized { fn input(src: &mut I) -> Self; } impl InputParse for Vec { fn input(src: &mut I) -> Self { src.bytes().to_owned() } } macro_rules! from_str_impl { { $($T:ty)* } => { $(impl InputParse for $T { fn input(src: &mut I) -> Self { src.str().parse::<$T>().unwrap() } })* } } from_str_impl! { String char bool f32 f64 } macro_rules! parse_int_impl { { $($I:ty: $U:ty)* } => { $(impl InputParse for $I { fn input(src: &mut I) -> Self { let f = |s: &[u8]| s.iter().fold(0, |x, b| 10 * x + (b & 0xf) as $I); let s = src.bytes(); if let Some((&b'-', t)) = s.split_first() { -f(t) } else { f(s) } } } impl InputParse for $U { fn input(src: &mut I) -> Self { src.bytes().iter().fold(0, |x, b| 10 * x + (b & 0xf) as $U) } })* }; } parse_int_impl! { isize:usize i8:u8 i16:u16 i32:u32 i64:u64 i128:u128 } macro_rules! tuple_impl { ($H:ident $($T:ident)*) => { impl<$H: InputParse, $($T: InputParse),*> InputParse for ($H, $($T),*) { fn input(src: &mut I) -> Self { ($H::input(src), $($T::input(src)),*) } } tuple_impl!($($T)*); }; () => {} } tuple_impl!(A B C D E F G); macro_rules! array_impl { { $($N:literal)* } => { $(impl InputParse for [T; $N] { fn input(src: &mut I) -> Self { let mut arr = mem::MaybeUninit::uninit(); unsafe { let ptr = arr.as_mut_ptr() as *mut T; for i in 0..$N { ptr.add(i).write(src.input()); } arr.assume_init() } } })* }; } array_impl! { 1 2 3 4 5 6 7 8 } #[macro_export] macro_rules! kdbg { ($($v:expr),*) => { if cfg!(debug_assertions) { dbg!($($v),*) } else { ($($v),*) } } } }