Problem p03332 (C++)

Buggy submission (status: Runtime Error):
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;

template <typename T1, typename T2>
string print_iterable(T1 begin_iter, T2 end_iter, int counter) {
  bool done_something = false;
  stringstream res;
  res << "[";
  for (; begin_iter != end_iter and counter; ++begin_iter) {
    done_something = true;
    counter--;
    res << *begin_iter << ", ";
  }
  string str = res.str();
  if (done_something) {
    str.pop_back();
    str.pop_back();
  }
  str += "]";
  return str;
}

vector<int> SortIndex(int size, std::function<bool(int, int)> compare) {
  vector<int> ord(size);
  for (int i = 0; i < size; i++)
    ord[i] = i;
  sort(ord.begin(), ord.end(), compare);
  return ord;
}

template <typename T> bool MinPlace(T &a, const T &b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}

template <typename T> bool MaxPlace(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

template <typename Container> int SZ(const Container &S) { return S.size(); }

template <typename S, typename T>
ostream &operator<<(ostream &out, const pair<S, T> &p) {
  out << "{" << p.first << ", " << p.second << "}";
  return out;
}

template <typename T> ostream &operator<<(ostream &out, const vector<T> &v) {
  out << "[";
  for (int i = 0; i < (int)v.size(); i++) {
    out << v[i];
    if (i != (int)v.size() - 1)
      out << ", ";
  }
  out << "]";
  return out;
}

#if DEBUG && !ONLINE_JUDGE
ifstream input_from_file("input.txt");
#define cin input_from_file

#define dbg_var(x) clog << #x << ": " << x << endl;
#define dbg_array(x, len)                                                      \
  clog << #x << ": " << print_iterable(x, x + len, -1) << endl;
#else
#define dbg_var(x)
#define dbg_array(x, len)
#endif

///////////////////////////////////////////////////////////////////////////
//////////////////// DO NOT TOUCH BEFORE THIS LINE ////////////////////////
///////////////////////////////////////////////////////////////////////////

const int MAXN = 101000;

const LL mod = 998244353;
LL fact[MAXN], invfact[MAXN];

LL binom(LL N, LL M) {
  return (fact[N] * ((invfact[M] * invfact[N - M]) % mod)) % mod;
}

LL Inverse(LL n, LL m) {
  n %= m;
  if (n <= 1)
    return n; // Handles properly (n = 0, m = 1).
  return m - ((m * Inverse(m, n) - 1) / n);
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0); // Remove in problems with online queries!
  fact[0] = 1;
  for (int i = 1; i < MAXN; i++)
    fact[i] = (fact[i - 1] * i) % mod;
  for (int i = 0; i < MAXN; i++)
    invfact[i] = Inverse(fact[i], mod);
  LL N, A, B, K;
  cin >> N >> A >> B >> K;
  LL res = 0;
  for (LL i = 0; i <= N; i++) {
    LL s = K - A * i;
    if (s < 0 or s > N * B or s % B)
      continue;
    LL j = s / B;
    res += (binom(N, i) * binom(N, j)) % mod;
  }
  res %= mod;
  cout << res << "\n";
}


Fixed submission:
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;

template <typename T1, typename T2>
string print_iterable(T1 begin_iter, T2 end_iter, int counter) {
  bool done_something = false;
  stringstream res;
  res << "[";
  for (; begin_iter != end_iter and counter; ++begin_iter) {
    done_something = true;
    counter--;
    res << *begin_iter << ", ";
  }
  string str = res.str();
  if (done_something) {
    str.pop_back();
    str.pop_back();
  }
  str += "]";
  return str;
}

vector<int> SortIndex(int size, std::function<bool(int, int)> compare) {
  vector<int> ord(size);
  for (int i = 0; i < size; i++)
    ord[i] = i;
  sort(ord.begin(), ord.end(), compare);
  return ord;
}

template <typename T> bool MinPlace(T &a, const T &b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}

template <typename T> bool MaxPlace(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

template <typename Container> int SZ(const Container &S) { return S.size(); }

template <typename S, typename T>
ostream &operator<<(ostream &out, const pair<S, T> &p) {
  out << "{" << p.first << ", " << p.second << "}";
  return out;
}

template <typename T> ostream &operator<<(ostream &out, const vector<T> &v) {
  out << "[";
  for (int i = 0; i < (int)v.size(); i++) {
    out << v[i];
    if (i != (int)v.size() - 1)
      out << ", ";
  }
  out << "]";
  return out;
}

#if DEBUG && !ONLINE_JUDGE
ifstream input_from_file("input.txt");
#define cin input_from_file

#define dbg_var(x) clog << #x << ": " << x << endl;
#define dbg_array(x, len)                                                      \
  clog << #x << ": " << print_iterable(x, x + len, -1) << endl;
#else
#define dbg_var(x)
#define dbg_array(x, len)
#endif

///////////////////////////////////////////////////////////////////////////
//////////////////// DO NOT TOUCH BEFORE THIS LINE ////////////////////////
///////////////////////////////////////////////////////////////////////////

const int MAXN = 301000;

const LL mod = 998244353;
LL fact[MAXN], invfact[MAXN];

LL binom(LL N, LL M) {
  return (fact[N] * ((invfact[M] * invfact[N - M]) % mod)) % mod;
}

LL Inverse(LL n, LL m) {
  n %= m;
  if (n <= 1)
    return n; // Handles properly (n = 0, m = 1).
  return m - ((m * Inverse(m, n) - 1) / n);
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0); // Remove in problems with online queries!
  fact[0] = 1;
  for (int i = 1; i < MAXN; i++)
    fact[i] = (fact[i - 1] * i) % mod;
  for (int i = 0; i < MAXN; i++)
    invfact[i] = Inverse(fact[i], mod);
  LL N, A, B, K;
  cin >> N >> A >> B >> K;
  LL res = 0;
  for (LL i = 0; i <= N; i++) {
    LL s = K - A * i;
    if (s < 0 or s > N * B or s % B)
      continue;
    LL j = s / B;
    res += (binom(N, i) * binom(N, j)) % mod;
  }
  res %= mod;
  cout << res << "\n";
}