Language: C++

#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
//const int mod = 1e9 + 7;
const int mod = 998244353;
const ll infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;
void YesNo(bool j){cout << (j ? "Yes" : "No") << endl; return;}
void yesno(bool j){cout << (j ? "yes" : "no") << endl; return;}
template<class Head> void pt(Head&& head){cout << head << endl; return;}

struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint a) const {
    mint res(*this);
    return res+=a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res-=a;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res*=a;
  }
  mint pow(ll t) const {
    if (!t) return 1;//n乗を効率的に求める
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }

  // for prime mod
  mint inv() const {
    return pow(mod-2);
  }
  mint& operator/=(const mint a) {
    return (*this) *= a.inv();
  }
  mint operator/(const mint a) const {
    mint res(*this);
    return res/=a;
  }
};

mint f(int n) {
  if (n == 0) return 1;
  mint x = f(n/2);
  x *= x;
  if (n%2 == 1) x *= 2;
  return x;
}

mint choose(int n, int a) {
  mint x = 1, y = 1;
  rep(i,a) {
    x *= n-i;
    y *= i+1;
  }
  return x / y;
}
struct combination {
  vector<mint> fact, ifact;
  combination(int n):fact(n+1),ifact(n+1) {
    assert(n < mod);
    fact[0] = 1;
    for (int i = 1; i <= n; ++i) fact[i] = fact[i-1]*i;
    ifact[n] = fact[n].inv();
    for (int i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i;
  }
  mint operator()(int n, int k) {
    if (k < 0 || k > n) return 0;
    return fact[n]*ifact[k]*ifact[n-k];
  }
};



int dp[3000][3000];

int main() {
    int n, s;
    cin >> n >> s;
    vector<int> a(n);
    vector<mint> vec(3005);
    vec[0]=1;
    rep(i,3005) vec[i+1]=vec[i]*2;
    rep(i,n) cin >> a[i];
    rep(i,n) dp[1][a[i]]=1;
    for(int i=2; i<n+1; i++) {
        rep(j,s+1) {
            rep(k,n) {
                if(j<=a[i]) continue;
                dp[i][j]+=dp[i-1][j-a[i]];
            }
        }
    }
    mint ans=0;
    for(int i=1; i<n+1; i++) {
        ans+=dp[i][s]*vec[n-i];
    }
    cout << ans.x << endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:117:22: error: no match for 'operator*' (operand types are 'int' and '__gnu_cxx::__alloc_traits<std::allocator<mint>, mint>::value_type' {aka 'mint'})
  117 |         ans+=dp[i][s]*vec[n-i];
In file included from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127,
                 from a.cc:1:
/usr/include/c++/14/complex:400:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator*(const complex<_Tp>&, const complex<_Tp>&)'
  400 |     operator*(const complex<_Tp>& __x, const complex<_Tp>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/complex:400:5: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   mismatched types 'const std::complex<_Tp>' and 'int'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^
/usr/include/c++/14/complex:409:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator*(const complex<_Tp>&, const _Tp&)'
  409 |     operator*(const complex<_Tp>& __x, const _Tp& __y)
      |     ^~~~~~~~
/usr/include/c++/14/complex:409:5: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   mismatched types 'const std::complex<_Tp>' and 'int'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^
/usr/include/c++/14/complex:418:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator*(const _Tp&, const complex<_Tp>&)'
  418 |     operator*(const _Tp& __x, const complex<_Tp>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/complex:418:5: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   '__gnu_cxx::__alloc_traits<std::allocator<mint>, mint>::value_type' {aka 'mint'} is not derived from 'const std::complex<_Tp>'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^
In file included from /usr/include/c++/14/valarray:605,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166:
/usr/include/c++/14/bits/valarray_after.h:407:5: note: candidate: 'template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__multiplies, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__multiplies, typename _Dom1::value_type>::result_type> std::operator*(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)'
  407 |     _DEFINE_EXPR_BINARY_OPERATOR(*, struct std::__multiplies)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:407:5: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'int'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^
/usr/include/c++/14/bits/valarray_after.h:407:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__multiplies, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__multiplies, typename _Dom1::value_type>::result_type> std::operator*(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)'
  407 |     _DEFINE_EXPR_BINARY_OPERATOR(*, struct std::__multiplies)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:407:5: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'int'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^
/usr/include/c++/14/bits/valarray_after.h:407:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__multiplies, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__multiplies, typename _Dom1::value_type>::result_type> std::operator*(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  407 |     _DEFINE_EXPR_BINARY_OPERATOR(*, struct std::__multiplies)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:407:5: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   '__gnu_cxx::__alloc_traits<std::allocator<mint>, mint>::value_type' {aka 'mint'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^
/usr/include/c++/14/bits/valarray_after.h:407:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__multiplies, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__multiplies, typename _Dom1::value_type>::result_type> std::operator*(const _Expr<_Dom1, typename _Dom1::value_type>&, const valarray<typename _Dom::value_type>&)'
  407 |     _DEFINE_EXPR_BINARY_OPERATOR(*, struct std::__multiplies)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:407:5: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'int'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^
/usr/include/c++/14/bits/valarray_after.h:407:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__multiplies, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__multiplies, typename _Dom1::value_type>::result_type> std::operator*(const valarray<typename _Dom::value_type>&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  407 |     _DEFINE_EXPR_BINARY_OPERATOR(*, struct std::__multiplies)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:407:5: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   '__gnu_cxx::__alloc_traits<std::allocator<mint>, mint>::value_type' {aka 'mint'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^
/usr/include/c++/14/valarray:1198:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__multiplies, std::_ValArray, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__multiplies, _Tp>::result_type> std::operator*(const valarray<_Tp>&, const valarray<_Tp>&)'
 1198 | _DEFINE_BINARY_OPERATOR(*, __multiplies)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1198:1: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   mismatched types 'const std::valarray<_Tp>' and 'int'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^
/usr/include/c++/14/valarray:1198:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__multiplies, std::_ValArray, std::_Constant, _Tp, _Tp>, typename std::__fun<std::__multiplies, _Tp>::result_type> std::operator*(const valarray<_Tp>&, const typename valarray<_Tp>::value_type&)'
 1198 | _DEFINE_BINARY_OPERATOR(*, __multiplies)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1198:1: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   mismatched types 'const std::valarray<_Tp>' and 'int'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^
/usr/include/c++/14/valarray:1198:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__multiplies, std::_Constant, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__multiplies, _Tp>::result_type> std::operator*(const typename valarray<_Tp>::value_type&, const valarray<_Tp>&)'
 1198 | _DEFINE_BINARY_OPERATOR(*, __multiplies)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1198:1: note:   template argument deduction/substitution failed:
a.cc:117:30: note:   '__gnu_cxx::__alloc_traits<std::allocator<mint>, mint>::value_type' {aka 'mint'} is not derived from 'const std::valarray<_Tp>'
  117 |         ans+=dp[i][s]*vec[n-i];
      |                              ^