#include #include using namespace std; using namespace atcoder; // using mint = modint1000000007; // const int mod = 1000000007; using mint = modint998244353; const int mod = 998244353; // const int INF = 1e9; // const long long LINF = 1e18; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i, l, r) for (int i = (l); i < (r); ++i) #define rrep(i, n) for (int i = (n)-1; i >= 0; --i) #define rrep2(i, l, r) for (int i = (r)-1; i >= (l); --i) #define all(x) (x).begin(), (x).end() #define allR(x) (x).rbegin(), (x).rend() #define P pair template inline bool chmax(A& a, const B& b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A& a, const B& b) { if (a > b) { a = b; return true; } return false; } #ifndef KWM_T_MATH_MODINT_BINOM_HPP #define KWM_T_MATH_MODINT_BINOM_HPP #include #include namespace kwm_t::math::modint { /** * @brief 二項係数・順列・多項係数(modint用) * * 典型用途: * nCk, nPk, 多項係数 * * 計算量: * 前計算 O(N) * クエリ O(1) * * @tparam Mint modint型 (例: atcoder::static_modint) * * 制約 / 注意: * - mod は素数 * - n < mod(階乗が0にならない範囲) * * 使用例: * Binom C(2000000); * C.com(n, k); * * verified: */ template struct Binom { std::vector fact, ifact; Binom(int n = 2000006) { init(n); } void init(int n) { fact.resize(n + 1); ifact.resize(n + 1); fact[0] = 1; for (int i = 1; i <= n; ++i) { fact[i] = fact[i - 1] * i; } ifact[n] = fact[n].inv(); for (int i = n; i >= 1; --i) { ifact[i - 1] = ifact[i] * i; } } // nCk Mint com(int n, int k) const { if (k < 0 || k > n) return 0; return fact[n] * ifact[k] * ifact[n - k]; } Mint operator()(int n, int k) const { return com(n, k); } // nPk Mint perm(int n, int k) const { if (k < 0 || k > n) return 0; return fact[n] * ifact[n - k]; } // nCk (nが大きくkが小さい場合) Mint com_sub(long long n, long long k) const { if (k < 0 || k > n) return 0; if (n - k < k) k = n - k; assert(k < (int)fact.size()); Mint res = ifact[k]; for (long long i = 0; i < k; ++i) { res *= (n - i); } return res; } // 多項係数 template Mint multinomial(int n, const Ints&... ms) const { Mint res = fact[n]; int sum = 0; for (int m : {ms...}) { if (m < 0 || m > n) return 0; res *= ifact[m]; sum += m; } if (sum > n) return 0; res *= ifact[n - sum]; return res; } // 1/x Mint inv(int x) const { if (x < (int)fact.size()) { return fact[x - 1] * ifact[x]; } return Mint(x).inv(); } // nCk の逆数 Mint inv_com(int n, int k) const { if (k < 0 || k > n) return 0; return ifact[n] * fact[k] * fact[n - k]; } }; } // namespace kwm_t::math::modint #endif // KWM_T_MATH_MODINT_BINOM_HPP #ifndef KWM_T_MATH_FPS_FACTORIAL_HPP #define KWM_T_MATH_FPS_FACTORIAL_HPP #include namespace kwm_t::math::fps { /** * @brief 階乗・逆階乗テーブル * * fac[i] = i! * finv[i] = (i!)^{-1} * * @tparam mint modint型 */ template struct Factorial { int n; std::vector fac, finv; explicit Factorial(int n = 0) : n(n), fac(n + 1, 1), finv(n + 1, 1) { if (n == 0) return; for (int i = 2; i <= n; ++i) fac[i] = fac[i - 1] * i; finv[n] = fac[n].inv(); for (int i = n; i >= 1; --i) finv[i - 1] = finv[i] * i; } // nCk mint comb(int n, int k) const { if (k < 0 || n < k) return 0; return fac[n] * finv[k] * finv[n - k]; } mint binom(int n, int k) const { return comb(n, k); } // nPk mint perm(int n, int k) const { if (k < 0 || n < k) return 0; return fac[n] * finv[n - k]; } }; } // namespace kwm_t::math::fps #endif // KWM_T_MATH_FPS_FACTORIAL_HPP #ifndef KWM_T_MATH_FPS_FPS_HPP #define KWM_T_MATH_FPS_FPS_HPP #include #include // #include "factorial.hpp" #include "atcoder/convolution" namespace kwm_t::math::fps { template struct FormalPowerSeries : std::vector { FormalPowerSeries(const std::vector& vec) : std::vector(vec) {} using std::vector::vector; using std::vector::operator=; using F = FormalPowerSeries; using SparseFPS = std::vector>; F operator-() const { F res(*this); for (auto& e : res) e = -e; return res; } F& operator*=(const T& g) { for (auto& e : *this) e *= g; return *this; } F& operator/=(const T& g) { assert(g != T(0)); *this *= g.inv(); return *this; } F& operator+=(const F& g) { int n = this->size(), m = g.size(); for (int i = 0; i < std::min(n, m); ++i) (*this)[i] += g[i]; return *this; } F& operator-=(const F& g) { int n = this->size(), m = g.size(); for (int i = 0; i < std::min(n, m); ++i)(*this)[i] -= g[i]; return *this; } F& operator<<=(const int d) { int n = this->size(); if (d >= n) *this = F(n); this->insert(this->begin(), d, 0); this->resize(n); return *this; } F& operator>>=(const int d) { int n = this->size(); this->erase(this->begin(), this->begin() + min(n, d)); this->resize(n); return *this; } // O(n log n) F inv(int d = -1) const { int n = this->size(); assert(n != 0 && (*this)[0] != 0); if (d == -1) d = n; assert(d >= 0); F res{ (*this)[0].inv() }; for (int m = 1; m < d; m *= 2) { F f(this->begin(), this->begin() + std::min(n, 2 * m)); F g(res); f.resize(2 * m), atcoder::internal::butterfly(f); g.resize(2 * m), atcoder::internal::butterfly(g); for (int i = 0; i < 2 * m; ++i) f[i] *= g[i]; atcoder::internal::butterfly_inv(f); f.erase(f.begin(), f.begin() + m); f.resize(2 * m), atcoder::internal::butterfly(f); for (int i = 0; i < 2 * m; ++i) f[i] *= g[i]; atcoder::internal::butterfly_inv(f); T iz = T(2 * m).inv(); iz *= -iz; for (int i = 0; i < m; ++i) f[i] *= iz; res.insert(res.end(), f.begin(), f.begin() + m); } res.resize(d); return res; } F& add_inplace(const F& g, int d = -1) { int n = this->size(); if (d == -1) d = n; assert(d >= 0); this->resize(d); for (int i = 0; i < std::min(d, (int)g.size()); ++i) (*this)[i] += g[i]; return *this; } F& add_resize_inplace(const F& g) { return add_inplace(g, std::max((int)this->size(), (int)g.size())); } F add(const F& g, int d = -1) const { return F(*this).add_inplace(g, d); } F add_resize(const F& g) const { return F(*this).add_resize_inplace(g); } F& sub_inplace(const F& g, int d = -1) { int n = this->size(); if (d == -1) d = n; assert(d >= 0); this->resize(d); for (int i = 0; i < std::min(d, (int)g.size()); ++i) (*this)[i] -= g[i]; return *this; } F& sub_resize_inplace(const F& g) { return sub_inplace(g, std::max((int)this->size(), (int)g.size())); } F sub(const F& g, int d = -1) const { return F(*this).sub_inplace(g, d); } F sub_resize(const F& g) const { return F(*this).sub_resize_inplace(g); } // fast: FMT-friendly modulus only // O(n log n) F& multiply_inplace(const F& g, int d = -1) { int n = this->size(); if (d == -1) d = n; assert(d >= 0); *this = convolution(move(*this), g); this->resize(d); return *this; } F& multiply_resize_inplace(const F& g) { return multiply_inplace(g, (int)this->size() + (int)g.size() - 1); } F multiply(const F& g, const int d = -1) const { return F(*this).multiply_inplace(g, d); } F multiply_resize(const F& g) const { return F(*this).multiply_resize_inplace(g); } // O(n log n) F& divide_inplace(const F& g, int d = -1) { int n = this->size(); if (d == -1) d = n; assert(d >= 0); *this = convolution(move(*this), g.inv(d)); this->resize(d); return *this; } // F& divide_resize_inplace(const F& g) { return divide_inplace(g, (int)this->size() + (int)g.size() - 1); } F divide(const F& g, const int d = -1) const { return F(*this).divide_inplace(g, d); } // F divide_resize(const F& g) const { return F(*this).divide_resize_inplace(g); } // // naive // // O(n^2) // F &multiply_inplace(const F &g) { // int n = this->size(), m = g.size(); // rrep(i, n) { // (*this)[i] *= g[0]; // rep2(j, 1, min(i+1, m)) (*this)[i] += (*this)[i-j] * g[j]; // } // return *this; // } // F multiply(const F &g) const { return F(*this).multiply_inplace(g); } // // O(n^2) // F ÷_inplace(const F &g) { // assert(g[0] != T(0)); // T ig0 = g[0].inv(); // int n = this->size(), m = g.size(); // rep(i, n) { // rep2(j, 1, min(i+1, m)) (*this)[i] -= (*this)[i-j] * g[j]; // (*this)[i] *= ig0; // } // return *this; // } // F divide(const F &g) const { return F(*this).divide_inplace(g); } // sparse // O(nk) F& add_inplace(const SparseFPS& g, int d = -1) { int n = this->size(); if (d == -1) d = n; assert(d >= 0); this->resize(d); for (auto& [i, c] : g) { if (i >= d) break; (*this)[i] += c; } return *this; } F& add_resize_inplace(const SparseFPS& g) { int d = this->size(); if (!g.empty()) d = std::max(d, g.back().first + 1); return add_inplace(g, d); } F add(const SparseFPS& g, int d = -1) const { return F(*this).add_inplace(g, d); } F add_resize(const SparseFPS& g) const { return F(*this).add_resize_inplace(g); } // sparse sub // O(k) F& sub_inplace(const SparseFPS& g, int d = -1) { int n = this->size(); if (d == -1) d = n; assert(d >= 0); this->resize(d); for (auto& [i, c] : g) { if (i >= d) break; (*this)[i] -= c; } return *this; } F& sub_resize_inplace(const SparseFPS& g) { int d = this->size(); if (!g.empty()) d = std::max(d, g.back().first + 1); return sub_inplace(g, d); } F sub(const SparseFPS& g, int d = -1) const { return F(*this).sub_inplace(g, d); } F sub_resize(const SparseFPS& g) const { return F(*this).sub_resize_inplace(g); } F& multiply_inplace(SparseFPS g) { int n = this->size(); auto [d, c] = g.front(); if (d == 0) g.erase(g.begin()); else c = 0; for (int i = (n - 1); i >= 0; --i) { (*this)[i] *= c; for (auto& [j, b] : g) { if (j > i) break; (*this)[i] += (*this)[i - j] * b; } } return *this; } F& multiply_resize_inplace(SparseFPS g) { int d = this->size(); if (!g.empty()) d += g.back().first; this->resize(d); return multiply_inplace(std::move(g)); } F multiply(const SparseFPS& g) const { return F(*this).multiply_inplace(g); } F multiply_resize(const SparseFPS& g) const { return F(*this).multiply_resize_inplace(g); } // O(nk) F& divide_inplace(SparseFPS g) { int n = this->size(); auto [d, c] = g.front(); assert(d == 0 && c != T(0)); T ic = c.inv(); g.erase(g.begin()); for (int i = 0; i < n; ++i) { for (auto& [j, b] : g) { if (j > i) break; (*this)[i] -= (*this)[i - j] * b; } (*this)[i] *= ic; } return *this; } F divide(const SparseFPS& g) const { return F(*this).divide_inplace(g); } // divide by x^shift * h(x), where h(0) != 0 // return the removed shift amount // O(nk) int divide_shifted_inplace(std::vector> g) { int n = this->size(); assert(!g.empty()); int shift = g.front().first; // remove x^shift *this >>= shift; for (auto& [d, c] : g) d -= shift; assert(g.front().first == 0); assert(g.front().second != T(0)); divide_inplace(std::move(g)); return shift; } F divide_shifted(const std::vector>& g) const { return F(*this).divide_shifted_inplace(g); } // multiply and divide (1 + cz^d) // O(n) void multiply_inplace(const int d, const T c) { int n = this->size(); if (c == T(1)) for (int i = (n - d - 1); i >= 0; --i) (*this)[i + d] += (*this)[i]; else if (c == T(-1)) for (int i = (n - d - 1); i >= 0; --i) (*this)[i + d] -= (*this)[i]; else for (int i = (n - d - 1); i >= 0; --i) (*this)[i + d] += (*this)[i] * c; } // O(n) void divide_inplace(const int d, const T c) { int n = this->size(); if (c == T(1)) for (int i = 0; i < n - d; ++i) (*this)[i + d] -= (*this)[i]; else if (c == T(-1)) for (int i = 0; i < n - d; ++i) (*this)[i + d] += (*this)[i]; else for (int i = 0; i < n - d; ++i) (*this)[i + d] -= (*this)[i] * c; } // O(n) T eval(const T& a) const { T x(1), res(0); for (auto e : *this) res += e * x, x *= a; return res; } // O(n) F& integ_inplace() { int n = this->size(); assert(n > 0); if (n == 1) return *this = F{ 0 }; this->insert(this->begin(), 0); this->pop_back(); std::vector inv(n); inv[1] = 1; int p = T::mod(); for (int i = 2; i < n; ++i) inv[i] = -inv[p % i] * (p / i); for (int i = 2; i < n; ++i) (*this)[i] *= inv[i]; return *this; } F integ() const { return F(*this).integ_inplace(); } // O(n) F& deriv_inplace() { int n = this->size(); assert(n > 0); for (int i = 2; i < n; ++i) (*this)[i] *= i; this->erase(this->begin()); this->push_back(0); return *this; } F deriv() const { return F(*this).deriv_inplace(); } // O(n log n) F& log_inplace(int d = -1) { int n = this->size(); assert(n > 0 && (*this)[0] == 1); if (d == -1) d = n; assert(d >= 0); if (d < n) this->resize(d); F f_inv = this->inv(); this->deriv_inplace(); this->multiply_inplace(f_inv); this->integ_inplace(); return *this; } F log(const int d = -1) const { return F(*this).log_inplace(d); } // O(n log n) // https://arxiv.org/abs/1301.5804 (Figure 1, right) F& exp_inplace(int d = -1) { int n = this->size(); assert(n > 0 && (*this)[0] == 0); if (d == -1) d = n; assert(d >= 0); F g{ 1 }, g_fft{ 1, 1 }; (*this)[0] = 1; this->resize(d); F h_drv(this->deriv()); for (int m = 2; m < d; m *= 2) { // prepare F f_fft(this->begin(), this->begin() + m); f_fft.resize(2 * m), atcoder::internal::butterfly(f_fft); // Step 2.a' // { F _g(m); for (int i = 0; i < m; ++i) _g[i] = f_fft[i] * g_fft[i]; atcoder::internal::butterfly_inv(_g); _g.erase(_g.begin(), _g.begin() + m / 2); _g.resize(m), atcoder::internal::butterfly(_g); for (int i = 0; i < m; ++i) _g[i] *= g_fft[i]; atcoder::internal::butterfly_inv(_g); _g.resize(m / 2); _g /= T(-m) * m; g.insert(g.end(), _g.begin(), _g.begin() + m / 2); // } // Step 2.b'--d' F t(this->begin(), this->begin() + m); t.deriv_inplace(); // { // Step 2.b' F r{ h_drv.begin(), h_drv.begin() + m - 1 }; // Step 2.c' r.resize(m); atcoder::internal::butterfly(r); for (int i = 0; i < m; ++i) r[i] *= f_fft[i]; atcoder::internal::butterfly_inv(r); r /= -m; // Step 2.d' t += r; t.insert(t.begin(), t.back()); t.pop_back(); // } // Step 2.e' if (2 * m < d) { t.resize(2 * m); atcoder::internal::butterfly(t); g_fft = g; g_fft.resize(2 * m); atcoder::internal::butterfly(g_fft); for (int i = 0; i < 2 * m; ++i) t[i] *= g_fft[i]; atcoder::internal::butterfly_inv(t); t.resize(m); t /= 2 * m; } else { // この場合分けをしても数パーセントしか速くならない F g1(g.begin() + m / 2, g.end()); F s1(t.begin() + m / 2, t.end()); t.resize(m / 2); g1.resize(m), atcoder::internal::butterfly(g1); t.resize(m), atcoder::internal::butterfly(t); s1.resize(m), atcoder::internal::butterfly(s1); for (int i = 0; i < m; ++i) s1[i] = g_fft[i] * s1[i] + g1[i] * t[i]; for (int i = 0; i < m; ++i) t[i] *= g_fft[i]; atcoder::internal::butterfly_inv(t); atcoder::internal::butterfly_inv(s1); for (int i = 0; i < m / 2; ++i) t[i + m / 2] += s1[i]; t /= m; } // Step 2.f' F v(this->begin() + m, this->begin() + std::min(d, 2 * m)); v.resize(m); t.insert(t.begin(), m - 1, 0); t.push_back(0); t.integ_inplace(); for (int i = 0; i < m; ++i) v[i] -= t[m + i]; // Step 2.g' v.resize(2 * m); atcoder::internal::butterfly(v); for (int i = 0; i < 2 * m; ++i) v[i] *= f_fft[i]; atcoder::internal::butterfly_inv(v); v.resize(m); v /= 2 * m; // Step 2.h' for (int i = 0; i < std::min(d - m, m); ++i)(*this)[m + i] = v[i]; } return *this; } F exp(const int d = -1) const { return F(*this).exp_inplace(d); } // O(n log n) F& pow_inplace(const long long k, int d = -1) { int n = this->size(); if (d == -1) d = n; assert(d >= 0 && k >= 0); if (k == 0) { *this = F(d); if (d > 0) (*this)[0] = 1; return *this; } int l = 0; while (l < n && (*this)[l] == 0) ++l; if (l > (d - 1) / k || l == n) return *this = F(d); T c = (*this)[l]; this->erase(this->begin(), this->begin() + l); *this /= c; this->log_inplace(d - l * k); *this *= k; this->exp_inplace(); *this *= c.pow(k); this->insert(this->begin(), l * k, 0); return *this; } F pow(const long long k, const int d = -1) const { return F(*this).pow_inplace(k, d); } // O(n log n) F& shift_inplace(const T c) { int n = this->size(); auto fc = Factorial(n); for (int i = 0; i < n; ++i) (*this)[i] *= fc.fac[i]; reverse(this->begin(), this->end()); F g(n); T cp = 1; for (int i = 0; i < n; ++i) g[i] = cp * fc.finv[i], cp *= c; this->multiply_inplace(g, n); reverse(this->begin(), this->end()); for (int i = 0; i < n; ++i) (*this)[i] *= fc.finv[i]; return *this; } F shift(const T c) const { return F(*this).shift_inplace(c); } F operator*(const T& g) const { return F(*this) *= g; } F operator/(const T& g) const { return F(*this) /= g; } F operator+(const F& g) const { return F(*this) += g; } F operator-(const F& g) const { return F(*this) -= g; } F operator<<(const int d) const { return F(*this) <<= d; } F operator>>(const int d) const { return F(*this) >>= d; } F operator*(std::vector> g) const { return F(*this) *= g; } F operator/(std::vector> g) const { return F(*this) /= g; } }; } // namespace kwm_t::math::fps #endif // KWM_T_MATH_FPS_FPS_HPP int main() { std::ios::sync_with_stdio(false); std::cin.tie(nullptr); int n, m, k; cin >> n >> m >> k; m = n * (n - 1) / 2 - m;// 残す数。 int s = n - 2; kwm_t::math::modint::Binombinom; // 残り、last using fps = kwm_t::math::fps::FormalPowerSeries; using sfps = vector>; vector>dp(s + 1, vector(s + 2)); dp[s][1] = { 1 }; // K-1層目までを決める rep(_, k - 1) { vector>ndp(s + 1, vector(s + 2)); rep(i, s + 1)rep(j, s + 2) { if (dp[i][j].empty())continue; auto tmp = dp[i][j]; rep2(k, 1, i + 1) { sfps s = { {0,-1},{j,1} }; tmp.multiply_resize_inplace(s); auto ctmp = tmp * binom(i, k); s = { { k * (k - 1) / 2,1} }; ctmp.multiply_resize_inplace(s); ndp[i - k][k].add_resize_inplace(ctmp); } } dp.swap(ndp); } // K層 int lim = n * (n - 1) / 2; fps ldp(lim + 1, 0); rep(i, s + 1)rep(j, s + 2) { auto f = dp[i][j]; // ldp+= f * (x^j-1) * x^base if (f.empty())continue; int base = (j + 1) * i + i * (i - 1) / 2; sfps s = { {base,-1},{base + j,1} }; f.multiply_resize_inplace(s); ldp.add_resize_inplace(f); } mint ans = 0; rep2(i, m, lim + 1) ans += binom(i, m) * ldp[i]; cout << ans.val() << endl; return 0; }