Problem p02662 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
// #include <boost/multiprecision/cpp_int.hpp>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("O3")
#define REP(i, n) for (int i = 0; i < n; i++)
#define REPP(i, n) for (int i = 1; i <= n; i++)
#define ALL(obj) (obj).begin(), (obj).end()
#define EPS (1e-9)
#define INF (1e17)
#define PI (acos(-1))
// const double PI = acos(-1);
// const double EPS = 1e-15;
// long long INF=(long long)1E17;
// #define i_7 (long long)(1e9+7)
#define i_7 998'244'353
long mod(long a) {
  long long c = a % i_7;
  if (c >= 0)
    return c;
  return c + i_7;
}
long long po(long a, long b) {
  if (b == 0) {
    return 1;
  }

  long long z = po(a, b / 2);
  z = mod(z * z);
  if (b % 2 != 0) {
    z = mod(a * z);
  }
  return z;
}

bool prime_(int n) {
  if (n == 1) {
    return false;
  } else if (n == 2) {
    return true;
  } else {
    for (int i = 2; i <= std::sqrt(n); i++) {
      if (n % i == 0) {
        return false;
      }
    }
    return true;
  }
}

long long gcd_(long long a, long long b) {
  if (a < b) {
    std::swap(a, b);
  }
  if (a % b == 0) {
    return b;
  } else {
    return gcd_(b, a % b);
  }
}

long long lcm_(long long x, long long y) { return (x / gcd_(x, y)) * y; }

// using namespace std;
// using namespace boost::multiprecision;
// using namespace __gnu_pbds;

int main() {
  using namespace std;
  long long n, s;
  cin >> n >> s;
  long long a[n];
  REP(i, n) cin >> a[i];
  vector<vector<long long>> dp(n, vector<long long>(s + 1, 0));
  REP(i, n) {
    if (i == 0) {
      dp[i][0] = 2;
      dp[i][a[i]] = 1;
      continue;
    }
    REP(d, s + 1) {
      dp[i][d] = mod(dp[i - 1][d] * 2);
      if (d - a[i] >= 0) {
        dp[i][d] += dp[i - 1][d - a[i]];
        dp[i][d] = mod(dp[i][d]);
      }
    }
  }
  long long ans = dp[n - 1][s];
  cout << ans << endl;
  return 0;
}

Fixed submission:
#include <bits/stdc++.h>
// #include <boost/multiprecision/cpp_int.hpp>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("O3")
#define REP(i, n) for (int i = 0; i < n; i++)
#define REPP(i, n) for (int i = 1; i <= n; i++)
#define ALL(obj) (obj).begin(), (obj).end()
#define EPS (1e-9)
#define INF (1e17)
#define PI (acos(-1))
// const double PI = acos(-1);
// const double EPS = 1e-15;
// long long INF=(long long)1E17;
// #define i_7 (long long)(1e9+7)
#define i_7 998'244'353
long mod(long a) {
  long long c = a % i_7;
  if (c >= 0)
    return c;
  return c + i_7;
}
long long po(long a, long b) {
  if (b == 0) {
    return 1;
  }

  long long z = po(a, b / 2);
  z = mod(z * z);
  if (b % 2 != 0) {
    z = mod(a * z);
  }
  return z;
}

bool prime_(int n) {
  if (n == 1) {
    return false;
  } else if (n == 2) {
    return true;
  } else {
    for (int i = 2; i <= std::sqrt(n); i++) {
      if (n % i == 0) {
        return false;
      }
    }
    return true;
  }
}

long long gcd_(long long a, long long b) {
  if (a < b) {
    std::swap(a, b);
  }
  if (a % b == 0) {
    return b;
  } else {
    return gcd_(b, a % b);
  }
}

long long lcm_(long long x, long long y) { return (x / gcd_(x, y)) * y; }

// using namespace std;
// using namespace boost::multiprecision;
// using namespace __gnu_pbds;

int main() {
  using namespace std;
  long long n, s;
  cin >> n >> s;
  long long a[n];
  REP(i, n) cin >> a[i];
  vector<vector<long long>> dp(n, vector<long long>(s + 1, 0));
  REP(i, n) {
    if (i == 0) {
      dp[i][0] = 2;
      if (a[i] <= s)
        dp[i][a[i]] = 1;
      continue;
    }
    REP(d, s + 1) {
      dp[i][d] = mod(dp[i - 1][d] * 2);
      if (d - a[i] >= 0) {
        dp[i][d] += dp[i - 1][d - a[i]];
        dp[i][d] = mod(dp[i][d]);
      }
    }
  }
  long long ans = dp[n - 1][s];
  cout << ans << endl;
  return 0;
}