Problem p03270 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
#define FOR(v, a, b) for (int v = (a); v < (b); ++v)
#define FORE(v, a, b) for (int v = (a); v <= (b); ++v)
#define REP(v, n) FOR(v, 0, n)
#define REPE(v, n) FORE(v, 0, n)
#define REV(v, a, b) for (int v = (a); v >= (b); --v)
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define ITR(it, c) for (auto it = (c).begin(); it != (c).end(); ++it)
#define RITR(it, c) for (auto it = (c).rbegin(); it != (c).rend(); ++it)
#define EXIST(c, x) ((c).find(x) != (c).end())
#define LLI long long int
#define fst first
#define snd second

#ifdef DEBUG
#include <misc/C++/Debug.cpp>
#else
#define dump(x) ((void)0)
#endif

#define gcd __gcd

using namespace std;
template <class T> constexpr T lcm(T m, T n) { return m / gcd(m, n) * n; }

template <typename I> void join(ostream &ost, I s, I t, string d = " ") {
  for (auto i = s; i != t; ++i) {
    if (i != s)
      ost << d;
    ost << *i;
  }
  ost << endl;
}
template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &a : v)
    is >> a;
  return is;
}
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p) {
  is >> p.first >> p.second;
  return is;
}

template <typename T, typename U> bool chmin(T &a, const U &b) {
  return (a > b ? a = b, true : false);
}
template <typename T, typename U> bool chmax(T &a, const U &b) {
  return (a < b ? a = b, true : false);
}
template <typename T, size_t N, typename U>
void fill_array(T (&a)[N], const U &v) {
  fill((U *)a, (U *)(a + N), v);
}

const LLI mod = 998244353;

LLI power(LLI n, LLI p, LLI m) {
  LLI ret = 1;
  while (p > 0) {
    if (p & 1)
      (ret *= n) %= m;
    (n *= n) %= m;
    p /= 2;
  }
  return ret;
}

LLI mod_inv(LLI n, LLI p) { return power(n, p - 2, p); }

template <LLI mod> class Combination {
public:
  vector<LLI> facto = {1};
  vector<LLI> ifacto = {1};

  LLI factorial(LLI i) {
    if (i < 0)
      throw exception();
    if (facto.size() <= i)
      facto.resize(i + 1, -1);
    if (i == 0)
      return facto[0] = 1;
    LLI j = i;
    for (; j >= 0; --j)
      if (facto[j] != -1)
        break;
    for (LLI k = j + 1; k <= i; ++k)
      (facto[k] = facto[k - 1] * k) %= mod;
    return facto[i];
  }

  LLI factorial_inverse(LLI i) {
    if (i < 0)
      throw exception();
    if (ifacto.size() <= i)
      ifacto.resize(i + 1, -1);
    if (ifacto[i] != -1)
      return ifacto[i];
    return ifacto[i] = mod_inv(factorial(i), mod);
  }

  LLI P(LLI n, LLI k) {
    if (n < k)
      return 0;
    return (factorial(n) * factorial_inverse(n - k)) % mod;
  }

  LLI C(LLI n, LLI k) { return (P(n, k) * factorial_inverse(k)) % mod; }

  LLI H(LLI n, LLI k) { return C(n + k - 1, k); }
};

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  Combination<mod> com;
  dump(com.H(1, 3));

  int K, N;
  while (cin >> K >> N) {

    FORE(i, 2, 2 * K) {
      LLI ans = 0;

      int m = 0;
      FORE(j, 1, K) if (i - j >= 1 and i - j <= K and i - j > j)++ m;

      if (i % 2 == 0) {
        FORE(j, 0, m) {
          (ans += power(2, j, mod) * com.C(m, j) % mod *
                  com.H(K - 2 * m + j - 1, N - j) % mod) %=
              mod; // 2a=Kのaを選ばない
          (ans += power(2, j, mod) * com.C(m, j) % mod *
                  com.H(K - 2 * m + j - 1, N - j - 1) % mod) %=
              mod; // 2a=Kのaを選ぶ
        }
      } else {
        FORE(j, 0, m) {
          (ans += power(2, j, mod) * com.C(m, j) % mod *
                  com.H(K - 2 * m + j, N - j) % mod) %= mod;
        }
      }

      cout << ans << endl;
    }
  }

  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
#define FOR(v, a, b) for (int v = (a); v < (b); ++v)
#define FORE(v, a, b) for (int v = (a); v <= (b); ++v)
#define REP(v, n) FOR(v, 0, n)
#define REPE(v, n) FORE(v, 0, n)
#define REV(v, a, b) for (int v = (a); v >= (b); --v)
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define ITR(it, c) for (auto it = (c).begin(); it != (c).end(); ++it)
#define RITR(it, c) for (auto it = (c).rbegin(); it != (c).rend(); ++it)
#define EXIST(c, x) ((c).find(x) != (c).end())
#define LLI long long int
#define fst first
#define snd second

#ifdef DEBUG
#include <misc/C++/Debug.cpp>
#else
#define dump(x) ((void)0)
#endif

#define gcd __gcd

using namespace std;
template <class T> constexpr T lcm(T m, T n) { return m / gcd(m, n) * n; }

template <typename I> void join(ostream &ost, I s, I t, string d = " ") {
  for (auto i = s; i != t; ++i) {
    if (i != s)
      ost << d;
    ost << *i;
  }
  ost << endl;
}
template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &a : v)
    is >> a;
  return is;
}
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p) {
  is >> p.first >> p.second;
  return is;
}

template <typename T, typename U> bool chmin(T &a, const U &b) {
  return (a > b ? a = b, true : false);
}
template <typename T, typename U> bool chmax(T &a, const U &b) {
  return (a < b ? a = b, true : false);
}
template <typename T, size_t N, typename U>
void fill_array(T (&a)[N], const U &v) {
  fill((U *)a, (U *)(a + N), v);
}

const LLI mod = 998244353;

LLI power(LLI n, LLI p, LLI m) {
  LLI ret = 1;
  while (p > 0) {
    if (p & 1)
      (ret *= n) %= m;
    (n *= n) %= m;
    p /= 2;
  }
  return ret;
}

LLI mod_inv(LLI n, LLI p) { return power(n, p - 2, p); }

template <LLI mod> class Combination {
public:
  vector<LLI> facto = {1};
  vector<LLI> ifacto = {1};

  LLI factorial(LLI i) {
    if (i < 0)
      throw exception();
    if (facto.size() <= i)
      facto.resize(i + 1, -1);
    if (i == 0)
      return facto[0] = 1;
    LLI j = i;
    for (; j >= 0; --j)
      if (facto[j] != -1)
        break;
    for (LLI k = j + 1; k <= i; ++k)
      (facto[k] = facto[k - 1] * k) %= mod;
    return facto[i];
  }

  LLI factorial_inverse(LLI i) {
    if (i < 0)
      throw exception();
    if (ifacto.size() <= i)
      ifacto.resize(i + 1, -1);
    if (ifacto[i] != -1)
      return ifacto[i];
    return ifacto[i] = mod_inv(factorial(i), mod);
  }

  LLI P(LLI n, LLI k) {
    if (n < k)
      return 0;
    return (factorial(n) * factorial_inverse(n - k)) % mod;
  }

  LLI C(LLI n, LLI k) {
    if (n < k or n < 0 or k < 0)
      return 0;
    return (P(n, k) * factorial_inverse(k)) % mod;
  }

  LLI H(LLI n, LLI k) { return C(n + k - 1, k); }
};

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  Combination<mod> com;
  dump(com.H(1, 3));

  int K, N;
  while (cin >> K >> N) {

    FORE(i, 2, 2 * K) {
      LLI ans = 0;

      int m = 0;
      FORE(j, 1, K) if (i - j >= 1 and i - j <= K and i - j > j)++ m;

      if (i % 2 == 0) {
        FORE(j, 0, m) {
          (ans += power(2, j, mod) * com.C(m, j) % mod *
                  com.H(K - 2 * m + j - 1, N - j) % mod) %=
              mod; // 2a=Kのaを選ばない
          (ans += power(2, j, mod) * com.C(m, j) % mod *
                  com.H(K - 2 * m + j - 1, N - j - 1) % mod) %=
              mod; // 2a=Kのaを選ぶ
        }
      } else {
        FORE(j, 0, m) {
          (ans += power(2, j, mod) * com.C(m, j) % mod *
                  com.H(K - 2 * m + j, N - j) % mod) %= mod;
        }
      }

      cout << ans << endl;
    }
  }

  return 0;
}