Problem p02662 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <bitset>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <vector>

using namespace std;

#define DEBUG_ //!!$BDs=P;~$K%3%a%s%H%"%&%H(B!!
#ifdef DEBUG_
#define dump(x) cerr << #x << " = " << (x) << endl;
#else
#define dump(x) ;
#endif

#define equals(a, b) (fabs((a) - (b)) < EPS)
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define REP(i, n) FOR(i, 0, n)
#define SZ(x) ((int)(x).size())
#define pb push_back
#define eb emplace_back

// #define int long long

typedef long long LL;
typedef vector<int> VI;
typedef vector<LL> VL;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;

template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

template <typename T> std::string printVector(const std::vector<T> &data) {
  std::stringstream ss;
  std::ostream_iterator<T> out_it(ss, ", ");
  ss << "[";
  std::copy(data.begin(), data.end() - 1, out_it);
  ss << data.back() << "]";
  return ss.str();
}

template <typename T> void print_array(const T &ary, int size) {
  REP(i, size) { cout << ary[i] << " "; }
  cout << endl;
}

const int mod = 998244353;
const LL LINF = 1001002003004005006ll;
const int INF = 1001001001;
const double EPS = (1e-10);
const long double PI =
    3.14159265358979323846264338327950288419716939937510582097494459230781640628620899;
int dx[] = {0, 0, -1, 1};
int dy[] = {-1, 1, 0, 0};

struct mint {
  LL x; // typedef long long LL;
  mint(LL x = 0) : x(x >= 0 ? x % mod : x % mod + mod) {}
  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;
    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;
  }
};

signed main(int argc, char const *argv[]) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << setprecision(12);
  int N, S;
  cin >> N >> S;
  VL A(N);
  REP(i, N) cin >> A[i];
  LL dp[3010] = {};
  mint base_t = mint(2).pow(N - 1);
  LL base = base_t.x;
  mint tmp = mint(2).inv();
  LL two_inv = tmp.x;

  REP(i, N) {
    for (int j = 3005; j >= 0; j--) {
      if (j - A[i] >= 0) {
        // dp[j] += dp[j-A[i]] / 2;
        dp[j] += dp[j - A[i]] * two_inv;
        dp[j] %= mod;
      }
    }

    dp[A[i]] += base;
    dp[A[i]] %= mod;
  }
  cout << dp[S] << endl;
}

Error: TLE

Fixed submission:

#include <algorithm>
#include <bitset>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <vector>

using namespace std;

#define DEBUG_ //!!$BDs=P;~$K%3%a%s%H%"%&%H(B!!
#ifdef DEBUG_
#define dump(x) cerr << #x << " = " << (x) << endl;
#else
#define dump(x) ;
#endif

#define equals(a, b) (fabs((a) - (b)) < EPS)
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define REP(i, n) FOR(i, 0, n)
#define SZ(x) ((int)(x).size())
#define pb push_back
#define eb emplace_back

// #define int long long

typedef long long LL;
typedef vector<int> VI;
typedef vector<LL> VL;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;

template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

template <typename T> std::string printVector(const std::vector<T> &data) {
  std::stringstream ss;
  std::ostream_iterator<T> out_it(ss, ", ");
  ss << "[";
  std::copy(data.begin(), data.end() - 1, out_it);
  ss << data.back() << "]";
  return ss.str();
}

template <typename T> void print_array(const T &ary, int size) {
  REP(i, size) { cout << ary[i] << " "; }
  cout << endl;
}

const int mod = 998244353;
const LL LINF = 1001002003004005006ll;
const int INF = 1001001001;
const double EPS = (1e-10);
const long double PI =
    3.14159265358979323846264338327950288419716939937510582097494459230781640628620899;
int dx[] = {0, 0, -1, 1};
int dy[] = {-1, 1, 0, 0};

struct mint {
  LL x; // typedef long long LL;
  mint(LL x = 0) : x(x >= 0 ? x % mod : x % mod + mod) {}
  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;
    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;
  }
};

signed main(int argc, char const *argv[]) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << setprecision(12);
  int N, S;
  cin >> N >> S;
  VI A(N);
  REP(i, N) cin >> A[i];
  vector<mint> dp(3010);
  mint base = mint(2).pow(N - 1);

  REP(i, N) {
    for (int j = 3005; j >= 0; j--) {
      if (j - A[i] >= 0)
        dp[j] += dp[j - A[i]] / 2;
    }

    dp[A[i]] += base;
  }
  cout << dp[S].x << endl;
}