Problem p02662 (C++)

Buggy submission (status: Runtime Error):
#include "bits/stdc++.h"

using namespace std;

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef vector<PII> VPII;
typedef long long LL;
typedef vector<LL> VL;
typedef vector<VL> VVL;
typedef pair<LL, LL> PLL;
typedef vector<PLL> VPLL;
typedef priority_queue<int> PQ_DESC;
typedef priority_queue<int, vector<int>, greater<int>> PQ_ASC;
typedef priority_queue<PII> PQ_DESC_PII;
typedef priority_queue<PII, vector<PII>, greater<PII>> PQ_ASC_PII;

#define ALL(c) (c).begin(), (c).end()
#define PB push_back
#define MP make_pair
#define SORT_ASC(c) sort(ALL(c))
// #define SORT_DESC(c) sort(ALL(c), greater<typeof(*((c).begin()))>())
#define SORT_DESC(c) sort((c).rbegin(), (c).rend())
#define REV(c) reverse((c).begin(), (c).end())
#define SIZE(a) int((a).size())

#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define ROF(i, a, b) for (int i = (b - 1); i >= (a); --i)
#define REP(i, n) FOR(i, 0, n)
#define PER(i, n) ROF(i, 0, n)

const double EPS = 1e-10;
const double PI = acos(-1.0);
const int LARGE_INT = 1e9 + 100;
const int INF = 2e9 + 100;
const LL INF_LL = (LL)INF * (LL)INF;
const int MOD = 998244353;

// debug
#define dump(x) cerr << #x << " = " << (x) << endl;
#define debug(x)                                                               \
  cerr << #x << " = " << (x) << " (L" << __LINE__ << ")"                       \
       << " " << __FILE__ << endl;

LL modpow(LL a, LL n) {
  LL res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a % MOD;
    a = a * a % MOD;
    n >>= 1;
  }
  return res;
}

void Main() {
  LL n, s;
  cin >> n >> s;
  VL a(n);
  REP(i, n) { cin >> a[i]; }
  VVL dp(n);
  REP(i, n) { dp[i].resize(s); }

  if (a[0] <= s) {
    dp[0][a[0]] = 1;
  }
  // dp[0][0] = 1;

  FOR(i, 1, n) {
    REP(j, s + 1) {
      dp[i][j] += dp[i - 1][j] * 2;
      dp[i][j] %= MOD;

      if (j + a[i] <= s) {
        if (j == 0) {
          dp[i][j + a[i]] += modpow(2, i);
        } else {
          dp[i][j + a[i]] += dp[i - 1][j];
        }
        dp[i][j + a[i]] %= MOD;
      }
    }
  }

  cout << dp[n - 1][s] % MOD << endl;

  return;
}

int main() {
  cin.tie(nullptr);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  Main();
  return 0;
}

Fixed submission:
#include "bits/stdc++.h"

using namespace std;

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef vector<PII> VPII;
typedef long long LL;
typedef vector<LL> VL;
typedef vector<VL> VVL;
typedef pair<LL, LL> PLL;
typedef vector<PLL> VPLL;
typedef priority_queue<int> PQ_DESC;
typedef priority_queue<int, vector<int>, greater<int>> PQ_ASC;
typedef priority_queue<PII> PQ_DESC_PII;
typedef priority_queue<PII, vector<PII>, greater<PII>> PQ_ASC_PII;

#define ALL(c) (c).begin(), (c).end()
#define PB push_back
#define MP make_pair
#define SORT_ASC(c) sort(ALL(c))
// #define SORT_DESC(c) sort(ALL(c), greater<typeof(*((c).begin()))>())
#define SORT_DESC(c) sort((c).rbegin(), (c).rend())
#define REV(c) reverse((c).begin(), (c).end())
#define SIZE(a) int((a).size())

#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define ROF(i, a, b) for (int i = (b - 1); i >= (a); --i)
#define REP(i, n) FOR(i, 0, n)
#define PER(i, n) ROF(i, 0, n)

const double EPS = 1e-10;
const double PI = acos(-1.0);
const int LARGE_INT = 1e9 + 100;
const int INF = 2e9 + 100;
const LL INF_LL = (LL)INF * (LL)INF;
const int MOD = 998244353;

// debug
#define dump(x) cerr << #x << " = " << (x) << endl;
#define debug(x)                                                               \
  cerr << #x << " = " << (x) << " (L" << __LINE__ << ")"                       \
       << " " << __FILE__ << endl;

LL modpow(LL a, LL n) {
  LL res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a % MOD;
    a = a * a % MOD;
    n >>= 1;
  }
  return res;
}

void Main() {
  LL n, s;
  cin >> n >> s;
  VL a(n);
  REP(i, n) { cin >> a[i]; }
  VVL dp(n);
  REP(i, n) { dp[i].resize(s + 1); }

  if (a[0] <= s) {
    dp[0][a[0]] = 1;
  }
  // dp[0][0] = 1;

  FOR(i, 1, n) {
    REP(j, s + 1) {
      dp[i][j] += dp[i - 1][j] * 2;
      dp[i][j] %= MOD;

      if (j + a[i] <= s) {
        if (j == 0) {
          dp[i][j + a[i]] += modpow(2, i);
        } else {
          dp[i][j + a[i]] += dp[i - 1][j];
        }
        dp[i][j + a[i]] %= MOD;
      }
    }
  }

  cout << dp[n - 1][s] % MOD << endl;

  return;
}

int main() {
  cin.tie(nullptr);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  Main();
  return 0;
}