/** * date : 2021-11-24 22:03:31 */ #define NDEBUG using namespace std; // intrinstic #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // utility namespace Nyaan { using ll = long long; using i64 = long long; using u64 = unsigned long long; using i128 = __int128_t; using u128 = __uint128_t; template using V = vector; template using VV = vector>; using vi = vector; using vl = vector; using vd = V; using vs = V; using vvi = vector>; using vvl = vector>; template struct P : pair { template P(Args... args) : pair(args...) {} using pair::first; using pair::second; T &x() { return first; } const T &x() const { return first; } U &y() { return second; } const U &y() const { return second; } P &operator+=(const P &r) { first += r.first; second += r.second; return *this; } P &operator-=(const P &r) { first -= r.first; second -= r.second; return *this; } P &operator*=(const P &r) { first *= r.first; second *= r.second; return *this; } P operator+(const P &r) const { return P(*this) += r; } P operator-(const P &r) const { return P(*this) -= r; } P operator*(const P &r) const { return P(*this) *= r; } }; using pl = P; using pi = P; using vp = V; constexpr int inf = 1001001001; constexpr long long infLL = 4004004004004004004LL; template int sz(const T &t) { return t.size(); } template inline bool amin(T &x, U y) { return (y < x) ? (x = y, true) : false; } template inline bool amax(T &x, U y) { return (x < y) ? (x = y, true) : false; } template inline T Max(const vector &v) { return *max_element(begin(v), end(v)); } template inline T Min(const vector &v) { return *min_element(begin(v), end(v)); } template inline long long Sum(const vector &v) { return accumulate(begin(v), end(v), 0LL); } template int lb(const vector &v, const T &a) { return lower_bound(begin(v), end(v), a) - begin(v); } template int ub(const vector &v, const T &a) { return upper_bound(begin(v), end(v), a) - begin(v); } constexpr long long TEN(int n) { long long ret = 1, x = 10; for (; n; x *= x, n >>= 1) ret *= (n & 1 ? x : 1); return ret; } template pair mkp(const T &t, const U &u) { return make_pair(t, u); } template vector mkrui(const vector &v, bool rev = false) { vector ret(v.size() + 1); if (rev) { for (int i = int(v.size()) - 1; i >= 0; i--) ret[i] = v[i] + ret[i + 1]; } else { for (int i = 0; i < int(v.size()); i++) ret[i + 1] = ret[i] + v[i]; } return ret; }; template vector mkuni(const vector &v) { vector ret(v); sort(ret.begin(), ret.end()); ret.erase(unique(ret.begin(), ret.end()), ret.end()); return ret; } template vector mkord(int N, F f) { vector ord(N); iota(begin(ord), end(ord), 0); sort(begin(ord), end(ord), f); return ord; } template vector mkinv(vector &v) { int max_val = *max_element(begin(v), end(v)); vector inv(max_val + 1, -1); for (int i = 0; i < (int)v.size(); i++) inv[v[i]] = i; return inv; } } // namespace Nyaan // bit operation namespace Nyaan { __attribute__((target("popcnt"))) inline int popcnt(const u64 &a) { return _mm_popcnt_u64(a); } inline int lsb(const u64 &a) { return a ? __builtin_ctzll(a) : 64; } inline int ctz(const u64 &a) { return a ? __builtin_ctzll(a) : 64; } inline int msb(const u64 &a) { return a ? 63 - __builtin_clzll(a) : -1; } template inline int gbit(const T &a, int i) { return (a >> i) & 1; } template inline void sbit(T &a, int i, bool b) { if (gbit(a, i) != b) a ^= T(1) << i; } constexpr long long PW(int n) { return 1LL << n; } constexpr long long MSK(int n) { return (1LL << n) - 1; } } // namespace Nyaan // inout namespace Nyaan { template ostream &operator<<(ostream &os, const pair &p) { os << p.first << " " << p.second; return os; } template istream &operator>>(istream &is, pair &p) { is >> p.first >> p.second; return is; } template ostream &operator<<(ostream &os, const vector &v) { int s = (int)v.size(); for (int i = 0; i < s; i++) os << (i ? " " : "") << v[i]; return os; } template istream &operator>>(istream &is, vector &v) { for (auto &x : v) is >> x; return is; } void in() {} template void in(T &t, U &... u) { cin >> t; in(u...); } void out() { cout << "\n"; } template void out(const T &t, const U &... u) { cout << t; if (sizeof...(u)) cout << sep; out(u...); } void outr() {} template void outr(const T &t, const U &... u) { cout << t; outr(u...); } struct IoSetupNya { IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(7); } } iosetupnya; } // namespace Nyaan // debug namespace DebugImpl { template struct is_specialize : false_type {}; template struct is_specialize< U, typename conditional::type> : true_type {}; template struct is_specialize< U, typename conditional::type> : true_type {}; template struct is_specialize::value, void>> : true_type { }; void dump(const char& t) { cerr << t; } void dump(const string& t) { cerr << t; } void dump(const bool& t) { cerr << (t ? "true" : "false"); } template ::value, nullptr_t> = nullptr> void dump(const U& t) { cerr << t; } template void dump(const T& t, enable_if_t::value>* = nullptr) { string res; if (t == Nyaan::inf) res = "inf"; if constexpr (is_signed::value) { if (t == -Nyaan::inf) res = "-inf"; } if constexpr (sizeof(T) == 8) { if (t == Nyaan::infLL) res = "inf"; if constexpr (is_signed::value) { if (t == -Nyaan::infLL) res = "-inf"; } } if (res.empty()) res = to_string(t); cerr << res; } template void dump(const pair&); template void dump(const pair&); template void dump(const T& t, enable_if_t::value>* = nullptr) { cerr << "[ "; for (auto it = t.begin(); it != t.end();) { dump(*it); cerr << (++it == t.end() ? "" : ", "); } cerr << " ]"; } template void dump(const pair& t) { cerr << "( "; dump(t.first); cerr << ", "; dump(t.second); cerr << " )"; } template void dump(const pair& t) { cerr << "[ "; for (int i = 0; i < t.second; i++) { dump(t.first[i]); cerr << (i == t.second - 1 ? "" : ", "); } cerr << " ]"; } void trace() { cerr << endl; } template void trace(Head&& head, Tail&&... tail) { cerr << " "; dump(head); if (sizeof...(tail) != 0) cerr << ","; trace(forward(tail)...); } } // namespace DebugImpl #ifdef NyaanDebug #define trc(...) \ do { \ cerr << "## " << #__VA_ARGS__ << " = "; \ DebugImpl::trace(__VA_ARGS__); \ } while (0) #else #define trc(...) (void(0)) #endif // macro #define each(x, v) for (auto&& x : v) #define each2(x, y, v) for (auto&& [x, y] : v) #define all(v) (v).begin(), (v).end() #define rep(i, N) for (long long i = 0; i < (long long)(N); i++) #define repr(i, N) for (long long i = (long long)(N)-1; i >= 0; i--) #define rep1(i, N) for (long long i = 1; i <= (long long)(N); i++) #define repr1(i, N) for (long long i = (N); (long long)(i) > 0; i--) #define reg(i, a, b) for (long long i = (a); i < (b); i++) #define regr(i, a, b) for (long long i = (b)-1; i >= (a); i--) #define fi first #define se second #define ini(...) \ int __VA_ARGS__; \ in(__VA_ARGS__) #define inl(...) \ long long __VA_ARGS__; \ in(__VA_ARGS__) #define ins(...) \ string __VA_ARGS__; \ in(__VA_ARGS__) #define in2(s, t) \ for (int i = 0; i < (int)s.size(); i++) { \ in(s[i], t[i]); \ } #define in3(s, t, u) \ for (int i = 0; i < (int)s.size(); i++) { \ in(s[i], t[i], u[i]); \ } #define in4(s, t, u, v) \ for (int i = 0; i < (int)s.size(); i++) { \ in(s[i], t[i], u[i], v[i]); \ } #define die(...) \ do { \ Nyaan::out(__VA_ARGS__); \ return; \ } while (0) namespace Nyaan { void solve(); } int main() { Nyaan::solve(); } // template struct edge { int src, to; T cost; edge(int _to, T _cost) : src(-1), to(_to), cost(_cost) {} edge(int _src, int _to, T _cost) : src(_src), to(_to), cost(_cost) {} edge &operator=(const int &x) { to = x; return *this; } operator int() const { return to; } }; template using Edges = vector>; template using WeightedGraph = vector>; using UnweightedGraph = vector>; // Input of (Unweighted) Graph UnweightedGraph graph(int N, int M = -1, bool is_directed = false, bool is_1origin = true) { UnweightedGraph g(N); if (M == -1) M = N - 1; for (int _ = 0; _ < M; _++) { int x, y; cin >> x >> y; if (is_1origin) x--, y--; g[x].push_back(y); if (!is_directed) g[y].push_back(x); } return g; } // Input of Weighted Graph template WeightedGraph wgraph(int N, int M = -1, bool is_directed = false, bool is_1origin = true) { WeightedGraph g(N); if (M == -1) M = N - 1; for (int _ = 0; _ < M; _++) { int x, y; cin >> x >> y; T c; cin >> c; if (is_1origin) x--, y--; g[x].emplace_back(x, y, c); if (!is_directed) g[y].emplace_back(y, x, c); } return g; } // Input of Edges template Edges esgraph(int N, int M, int is_weighted = true, bool is_1origin = true) { Edges es; for (int _ = 0; _ < M; _++) { int x, y; cin >> x >> y; T c; if (is_weighted) cin >> c; else c = 1; if (is_1origin) x--, y--; es.emplace_back(x, y, c); } return es; } // Input of Adjacency Matrix template vector> adjgraph(int N, int M, T INF, int is_weighted = true, bool is_directed = false, bool is_1origin = true) { vector> d(N, vector(N, INF)); for (int _ = 0; _ < M; _++) { int x, y; cin >> x >> y; T c; if (is_weighted) cin >> c; else c = 1; if (is_1origin) x--, y--; d[x][y] = c; if (!is_directed) d[y][x] = c; } return d; } // namespace HashMapImpl { using u32 = uint32_t; using u64 = uint64_t; template struct HashMapBase; template struct itrB : iterator { using base = iterator; using ptr = typename base::pointer; using ref = typename base::reference; u32 i; HashMapBase* p; explicit constexpr itrB() : i(0), p(nullptr) {} explicit constexpr itrB(u32 _i, HashMapBase* _p) : i(_i), p(_p) {} explicit constexpr itrB(u32 _i, const HashMapBase* _p) : i(_i), p(const_cast*>(_p)) {} friend void swap(itrB& l, itrB& r) { swap(l.i, r.i), swap(l.p, r.p); } friend bool operator==(const itrB& l, const itrB& r) { return l.i == r.i; } friend bool operator!=(const itrB& l, const itrB& r) { return l.i != r.i; } const ref operator*() const { return const_cast*>(p)->data[i]; } ref operator*() { return p->data[i]; } ptr operator->() const { return &(p->data[i]); } itrB& operator++() { assert(i != p->cap && "itr::operator++()"); do { i++; if (i == p->cap) break; if (p->flag[i] == true && p->dflag[i] == false) break; } while (true); return (*this); } itrB operator++(int) { itrB it(*this); ++(*this); return it; } itrB& operator--() { do { i--; if (p->flag[i] == true && p->dflag[i] == false) break; assert(i != 0 && "itr::operator--()"); } while (true); return (*this); } itrB operator--(int) { itrB it(*this); --(*this); return it; } }; template struct HashMapBase { using u32 = uint32_t; using u64 = uint64_t; using iterator = itrB; using itr = iterator; protected: template inline u64 randomized(const K& key) const { return u64(key) ^ r; } template ::value, nullptr_t> = nullptr, enable_if_t::value, nullptr_t> = nullptr> inline u32 inner_hash(const K& key) const { return (randomized(key) * 11995408973635179863ULL) >> shift; } template < typename K, enable_if_t::value, nullptr_t> = nullptr, enable_if_t::value, nullptr_t> = nullptr, enable_if_t::value, nullptr_t> = nullptr> inline u32 inner_hash(const K& key) const { u64 a = randomized(key.first), b = randomized(key.second); a *= 11995408973635179863ULL; b *= 10150724397891781847ULL; return (a + b) >> shift; } template ::value, nullptr_t> = nullptr, enable_if_t::value, nullptr_t> = nullptr> inline u32 inner_hash(const K& key) const { static constexpr u64 mod = (1LL << 61) - 1; static constexpr u64 base = 950699498548472943ULL; u64 res = 0; for (auto& elem : key) { __uint128_t x = __uint128_t(res) * base + (randomized(elem) & mod); res = (x & mod) + (x >> 61); } __uint128_t x = __uint128_t(res) * base; res = (x & mod) + (x >> 61); if (res >= mod) res -= mod; return res >> (shift - 3); } template ::value, nullptr_t> = nullptr> inline u32 hash(const D& dat) const { return inner_hash(dat); } template < typename D = Data, enable_if_t::value, nullptr_t> = nullptr> inline u32 hash(const D& dat) const { return inner_hash(dat.first); } template ::value, nullptr_t> = nullptr> inline Key dtok(const D& dat) const { return dat; } template < typename D = Data, enable_if_t::value, nullptr_t> = nullptr> inline Key dtok(const D& dat) const { return dat.first; } void reallocate(u32 ncap) { vector ndata(ncap); vector nf(ncap); shift = 64 - __lg(ncap); for (u32 i = 0; i < cap; i++) { if (flag[i] == true && dflag[i] == false) { u32 h = hash(data[i]); while (nf[h]) h = (h + 1) & (ncap - 1); ndata[h] = move(data[i]); nf[h] = true; } } data.swap(ndata); flag.swap(nf); cap = ncap; dflag.resize(cap); fill(std::begin(dflag), std::end(dflag), false); } inline bool extend_rate(u32 x) const { return x * 2 >= cap; } inline bool shrink_rate(u32 x) const { return HASHMAP_DEFAULT_SIZE < cap && x * 10 <= cap; } inline void extend() { reallocate(cap << 1); } inline void shrink() { reallocate(cap >> 1); } public: u32 cap, s; vector data; vector flag, dflag; u32 shift; static u64 r; static constexpr uint32_t HASHMAP_DEFAULT_SIZE = 4; explicit HashMapBase() : cap(HASHMAP_DEFAULT_SIZE), s(0), data(cap), flag(cap), dflag(cap), shift(64 - __lg(cap)) {} itr begin() const { u32 h = 0; while (h != cap) { if (flag[h] == true && dflag[h] == false) break; h++; } return itr(h, this); } itr end() const { return itr(this->cap, this); } friend itr begin(const HashMapBase& h) { return h.begin(); } friend itr end(const HashMapBase& h) { return h.end(); } itr find(const Key& key) const { u32 h = inner_hash(key); while (true) { if (flag[h] == false) return this->end(); if (dtok(data[h]) == key) { if (dflag[h] == true) return this->end(); return itr(h, this); } h = (h + 1) & (cap - 1); } } bool contain(const Key& key) const { return find(key) != this->end(); } itr insert(const Data& d) { u32 h = hash(d); while (true) { if (flag[h] == false) { if (extend_rate(s + 1)) { extend(); h = hash(d); continue; } data[h] = d; flag[h] = true; ++s; return itr(h, this); } if (dtok(data[h]) == dtok(d)) { if (dflag[h] == true) { data[h] = d; dflag[h] = false; ++s; } return itr(h, this); } h = (h + 1) & (cap - 1); } } // tips for speed up : // if return value is unnecessary, make argument_2 false. itr erase(itr it, bool get_next = true) { if (it == this->end()) return this->end(); s--; if (shrink_rate(s)) { Data d = data[it.i]; shrink(); it = find(dtok(d)); } int ni = (it.i + 1) & (cap - 1); if (this->flag[ni]) { this->dflag[it.i] = true; } else { this->flag[it.i] = false; } if (get_next) ++it; return it; } itr erase(const Key& key) { return erase(find(key)); } bool empty() const { return s == 0; } int size() const { return s; } void clear() { fill(std::begin(flag), std::end(flag), false); fill(std::begin(dflag), std::end(dflag), false); s = 0; } void reserve(int n) { if (n <= 0) return; n = 1 << min(23, __lg(n) + 2); if (cap < u32(n)) reallocate(n); } }; template uint64_t HashMapBase::r = chrono::duration_cast( chrono::high_resolution_clock::now().time_since_epoch()) .count(); } // namespace HashMapImpl /** * @brief Hash Map(base) (ハッシュマップ・基底クラス) */ template struct HashMap : HashMapImpl::HashMapBase> { using base = typename HashMapImpl::HashMapBase>; using HashMapImpl::HashMapBase>::HashMapBase; using Data = pair; Val& operator[](const Key& k) { typename base::u32 h = base::inner_hash(k); while (true) { if (base::flag[h] == false) { if (base::extend_rate(base::s + 1)) { base::extend(); h = base::hash(k); continue; } base::data[h].first = k; base::data[h].second = Val(); base::flag[h] = true; ++base::s; return base::data[h].second; } if (base::data[h].first == k) { if (base::dflag[h] == true) base::data[h].second = Val(); return base::data[h].second; } h = (h + 1) & (base::cap - 1); } } typename base::itr emplace(const Key& key, const Val& val) { return base::insert(Data(key, val)); } }; /* * @brief ハッシュマップ(連想配列) * @docs docs/hashmap/hashmap.md **/ // template std::pair GaussElimination(vector> &a, int pivot_end = -1, bool diagonalize = false) { int H = a.size(), W = a[0].size(); int rank = 0, je = pivot_end; if (je == -1) je = W; mint det = 1; for (int j = 0; j < je; j++) { int idx = -1; for (int i = rank; i < H; i++) { if (a[i][j] != mint(0)) { idx = i; break; } } if (idx == -1) { det = 0; continue; } if (rank != idx) { det = -det; swap(a[rank], a[idx]); } det *= a[rank][j]; if (diagonalize && a[rank][j] != mint(1)) { mint coeff = a[rank][j].inverse(); for (int k = j; k < W; k++) a[rank][k] *= coeff; } int is = diagonalize ? 0 : rank + 1; for (int i = is; i < H; i++) { if (i == rank) continue; if (a[i][j] != mint(0)) { mint coeff = a[i][j] / a[rank][j]; for (int k = j; k < W; k++) a[i][k] -= a[rank][k] * coeff; } } rank++; } return make_pair(rank, det); } template vector> LinearEquation(vector> a, vector b) { int H = a.size(), W = a[0].size(); for (int i = 0; i < H; i++) a[i].push_back(b[i]); auto p = GaussElimination(a, W, true); int rank = p.first; for (int i = rank; i < H; ++i) { if (a[i][W] != 0) return vector>{}; } vector> res(1, vector(W)); vector pivot(W, -1); for (int i = 0, j = 0; i < rank; ++i) { while (a[i][j] == 0) ++j; res[0][j] = a[i][W], pivot[j] = i; } for (int j = 0; j < W; ++j) { if (pivot[j] == -1) { vector x(W); x[j] = 1; for (int k = 0; k < j; ++k) { if (pivot[k] != -1) x[k] = -a[pivot[k]][j]; } res.push_back(x); } } return res; } // template struct FormalPowerSeries : vector { using vector::vector; using FPS = FormalPowerSeries; FPS &operator+=(const FPS &r) { if (r.size() > this->size()) this->resize(r.size()); for (int i = 0; i < (int)r.size(); i++) (*this)[i] += r[i]; return *this; } FPS &operator+=(const mint &r) { if (this->empty()) this->resize(1); (*this)[0] += r; return *this; } FPS &operator-=(const FPS &r) { if (r.size() > this->size()) this->resize(r.size()); for (int i = 0; i < (int)r.size(); i++) (*this)[i] -= r[i]; return *this; } FPS &operator-=(const mint &r) { if (this->empty()) this->resize(1); (*this)[0] -= r; return *this; } FPS &operator*=(const mint &v) { for (int k = 0; k < (int)this->size(); k++) (*this)[k] *= v; return *this; } FPS &operator/=(const FPS &r) { if (this->size() < r.size()) { this->clear(); return *this; } int n = this->size() - r.size() + 1; if ((int)r.size() <= 64) { FPS f(*this), g(r); g.shrink(); mint coeff = g.back().inverse(); for (auto &x : g) x *= coeff; int deg = (int)f.size() - (int)g.size() + 1; int gs = g.size(); FPS quo(deg); for (int i = deg - 1; i >= 0; i--) { quo[i] = f[i + gs - 1]; for (int j = 0; j < gs; j++) f[i + j] -= quo[i] * g[j]; } *this = quo * coeff; this->resize(n, mint(0)); return *this; } return *this = ((*this).rev().pre(n) * r.rev().inv(n)).pre(n).rev(); } FPS &operator%=(const FPS &r) { *this -= *this / r * r; shrink(); return *this; } FPS operator+(const FPS &r) const { return FPS(*this) += r; } FPS operator+(const mint &v) const { return FPS(*this) += v; } FPS operator-(const FPS &r) const { return FPS(*this) -= r; } FPS operator-(const mint &v) const { return FPS(*this) -= v; } FPS operator*(const FPS &r) const { return FPS(*this) *= r; } FPS operator*(const mint &v) const { return FPS(*this) *= v; } FPS operator/(const FPS &r) const { return FPS(*this) /= r; } FPS operator%(const FPS &r) const { return FPS(*this) %= r; } FPS operator-() const { FPS ret(this->size()); for (int i = 0; i < (int)this->size(); i++) ret[i] = -(*this)[i]; return ret; } void shrink() { while (this->size() && this->back() == mint(0)) this->pop_back(); } FPS rev() const { FPS ret(*this); reverse(begin(ret), end(ret)); return ret; } FPS dot(FPS r) const { FPS ret(min(this->size(), r.size())); for (int i = 0; i < (int)ret.size(); i++) ret[i] = (*this)[i] * r[i]; return ret; } FPS pre(int sz) const { return FPS(begin(*this), begin(*this) + min((int)this->size(), sz)); } FPS operator>>(int sz) const { if ((int)this->size() <= sz) return {}; FPS ret(*this); ret.erase(ret.begin(), ret.begin() + sz); return ret; } FPS operator<<(int sz) const { FPS ret(*this); ret.insert(ret.begin(), sz, mint(0)); return ret; } FPS diff() const { const int n = (int)this->size(); FPS ret(max(0, n - 1)); mint one(1), coeff(1); for (int i = 1; i < n; i++) { ret[i - 1] = (*this)[i] * coeff; coeff += one; } return ret; } FPS integral() const { const int n = (int)this->size(); FPS ret(n + 1); ret[0] = mint(0); if (n > 0) ret[1] = mint(1); auto mod = mint::get_mod(); for (int i = 2; i <= n; i++) ret[i] = (-ret[mod % i]) * (mod / i); for (int i = 0; i < n; i++) ret[i + 1] *= (*this)[i]; return ret; } mint eval(mint x) const { mint r = 0, w = 1; for (auto &v : *this) r += w * v, w *= x; return r; } FPS log(int deg = -1) const { assert((*this)[0] == mint(1)); if (deg == -1) deg = (int)this->size(); return (this->diff() * this->inv(deg)).pre(deg - 1).integral(); } FPS pow(int64_t k, int deg = -1) const { const int n = (int)this->size(); if (deg == -1) deg = n; for (int i = 0; i < n; i++) { if ((*this)[i] != mint(0)) { if (i * k > deg) return FPS(deg, mint(0)); mint rev = mint(1) / (*this)[i]; FPS ret = (((*this * rev) >> i).log(deg) * k).exp(deg) * ((*this)[i].pow(k)); ret = (ret << (i * k)).pre(deg); if ((int)ret.size() < deg) ret.resize(deg, mint(0)); return ret; } } return FPS(deg, mint(0)); } static void *ntt_ptr; static void set_fft(); FPS &operator*=(const FPS &r); void ntt(); void intt(); void ntt_doubling(); static int ntt_pr(); FPS inv(int deg = -1) const; FPS exp(int deg = -1) const; }; template void *FormalPowerSeries::ntt_ptr = nullptr; /** * @brief 多項式/形式的冪級数ライブラリ * @docs docs/fps/formal-power-series.md */ template struct LazyMontgomeryModInt { using mint = LazyMontgomeryModInt; using i32 = int32_t; using u32 = uint32_t; using u64 = uint64_t; static constexpr u32 get_r() { u32 ret = mod; for (i32 i = 0; i < 4; ++i) ret *= 2 - mod * ret; return ret; } static constexpr u32 r = get_r(); static constexpr u32 n2 = -u64(mod) % mod; static_assert(r * mod == 1, "invalid, r * mod != 1"); static_assert(mod < (1 << 30), "invalid, mod >= 2 ^ 30"); static_assert((mod & 1) == 1, "invalid, mod % 2 == 0"); u32 a; constexpr LazyMontgomeryModInt() : a(0) {} constexpr LazyMontgomeryModInt(const int64_t &b) : a(reduce(u64(b % mod + mod) * n2)){}; static constexpr u32 reduce(const u64 &b) { return (b + u64(u32(b) * u32(-r)) * mod) >> 32; } constexpr mint &operator+=(const mint &b) { if (i32(a += b.a - 2 * mod) < 0) a += 2 * mod; return *this; } constexpr mint &operator-=(const mint &b) { if (i32(a -= b.a) < 0) a += 2 * mod; return *this; } constexpr mint &operator*=(const mint &b) { a = reduce(u64(a) * b.a); return *this; } constexpr mint &operator/=(const mint &b) { *this *= b.inverse(); return *this; } constexpr mint operator+(const mint &b) const { return mint(*this) += b; } constexpr mint operator-(const mint &b) const { return mint(*this) -= b; } constexpr mint operator*(const mint &b) const { return mint(*this) *= b; } constexpr mint operator/(const mint &b) const { return mint(*this) /= b; } constexpr bool operator==(const mint &b) const { return (a >= mod ? a - mod : a) == (b.a >= mod ? b.a - mod : b.a); } constexpr bool operator!=(const mint &b) const { return (a >= mod ? a - mod : a) != (b.a >= mod ? b.a - mod : b.a); } constexpr mint operator-() const { return mint() - mint(*this); } constexpr mint pow(u64 n) const { mint ret(1), mul(*this); while (n > 0) { if (n & 1) ret *= mul; mul *= mul; n >>= 1; } return ret; } constexpr mint inverse() const { return pow(mod - 2); } friend ostream &operator<<(ostream &os, const mint &b) { return os << b.get(); } friend istream &operator>>(istream &is, mint &b) { int64_t t; is >> t; b = LazyMontgomeryModInt(t); return (is); } constexpr u32 get() const { u32 ret = reduce(a); return ret >= mod ? ret - mod : ret; } static constexpr u32 get_mod() { return mod; } }; template struct Binomial { vector f, g, h; Binomial(int MAX = 0) : f(1, T(1)), g(1, T(1)), h(1, T(1)) { while (MAX >= (int)f.size()) extend(); } void extend() { int n = f.size(); int m = n * 2; f.resize(m); g.resize(m); h.resize(m); for (int i = n; i < m; i++) f[i] = f[i - 1] * T(i); g[m - 1] = f[m - 1].inverse(); h[m - 1] = g[m - 1] * f[m - 2]; for (int i = m - 2; i >= n; i--) { g[i] = g[i + 1] * T(i + 1); h[i] = g[i] * f[i - 1]; } } T fac(int i) { if (i < 0) return T(0); while (i >= (int)f.size()) extend(); return f[i]; } T finv(int i) { if (i < 0) return T(0); while (i >= (int)g.size()) extend(); return g[i]; } T inv(int i) { if (i < 0) return -inv(-i); while (i >= (int)h.size()) extend(); return h[i]; } T C(int n, int r) { if (n < 0 || n < r || r < 0) return T(0); return fac(n) * finv(n - r) * finv(r); } inline T operator()(int n, int r) { return C(n, r); } template T multinomial(const vector& r) { static_assert(is_integral::value == true); int n = 0; for (auto& x : r) { if(x < 0) return T(0); n += x; } T res = fac(n); for (auto& x : r) res *= finv(x); return res; } template T operator()(const vector& r) { return multinomial(r); } T C_naive(int n, int r) { if (n < 0 || n < r || r < 0) return T(0); T ret = T(1); r = min(r, n - r); for (int i = 1; i <= r; ++i) ret *= inv(i) * (n--); return ret; } T P(int n, int r) { if (n < 0 || n < r || r < 0) return T(0); return fac(n) * finv(n - r); } T H(int n, int r) { if (n < 0 || r < 0) return T(0); return r == 0 ? 1 : C(n + r - 1, r); } }; // using namespace Nyaan; using mint = LazyMontgomeryModInt<998244353>; // using mint = LazyMontgomeryModInt<1000000007>; using vm = vector; using vvm = vector; using fps = FormalPowerSeries; Binomial C; using namespace Nyaan; void Nyaan::solve() { inl(N); map ws; Edges es; rep(i, N - 1) { inl(u, v, w); --u, --v; es.emplace_back(u, v, w); ws[w]++; } int X = 0, Y = 0; mint a = 0, b = 0; tie(a, X) = *begin(ws); if (sz(ws) == 2) tie(b, Y) = *next(begin(ws)); if (X > Y) swap(X, Y), swap(a, b); vector> A((X + 1) * (Y + 1)); // for(auto&h:A)h.reserve(Y); vector B((X + 1) * (Y + 1)); auto id = [&](int i, int j) { return i * (Y + 1) + j; }; rep(i, X + 1) rep(j, Y + 1) { if (i == X and j == Y) continue; mint p = N * (N - 1) / 2 - (X + Y - 1); mint q = N - i - j; if (i != 0) A[id(i, j)][id(i - 0, j)] += a * i * q; if (i != 0) A[id(i, j)][id(i - 1, j)] += a * i * (p - q); if (j != 0) A[id(i, j)][id(i, j - 0)] += b * j * q; if (j != 0) A[id(i, j)][id(i, j - 1)] += b * j * (p - q); if (i != X) A[id(i, j)][id(i + 0, j)] += a * (X - i) * (p - q + 1); if (i != X) A[id(i, j)][id(i + 1, j)] += a * (X - i) * (q - 1); if (j != Y) A[id(i, j)][id(i, j + 0)] += b * (Y - j) * (p - q + 1); if (j != Y) A[id(i, j)][id(i, j + 1)] += b * (Y - j) * (q - 1); mint all = (a * X + b * Y) * p; A[id(i, j)][id(i, j)] -= all; B[id(i, j)] = -all / N; } vector f((X + 1) * (Y + 1), fps(Y + 2)); rep(j, Y + 1) f[j][j] = 1; rep1(i, X) rep(j, Y + 1) { int imj = id(i - 1, j); int ij = id(i, j); auto& dst = f[ij]; auto& eq = A[imj]; each2(k, v, eq) { if (k == ij) continue; dst += f[k] * v; } dst[Y + 1] -= B[imj]; dst *= -eq[ij].inverse(); trc(dst, eq[ij]); } trc("f end"); vector mat(Y, vector(Y + 1)); vector vec(Y); { int i = X; rep(j, Y) { int ij = id(i, j); auto&eq = A[ij]; fps sm(Y + 2); each2(k, v, eq) sm += f[k] * v; sm[Y + 1] -= B[ij]; trc(sm); rep(k, Y + 1) mat[j][k] = sm[k]; vec[j] = -sm[Y + 1]; } } trc(mat); trc(vec); vm xs((X + 1) * (Y + 1)); { auto xs2 = LinearEquation(mat, vec)[0]; rep(i, (X + 1) * (Y + 1)) { xs[i] = f[i][Y + 1]; rep(j, Y + 1) xs[i] += f[i][j] * xs2[j]; } } vi cx(N), cy(N); each(e, es) { (a == e.cost ? cx : cy)[e.src]++; (a == e.cost ? cx : cy)[e.to]++; } trc(cx, cy); mint ans = 0; rep(i, N) ans += xs[id(cx[i], cy[i])]; ans -= xs[id(1, 0)] * X + xs[id(0, 1)] * Y + xs[id(X, Y)]; out(ans); }