/** * date : 2023-12-15 02:07:41 * author : Nyaan */ #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 using minpq = priority_queue, greater>; template struct P : pair { template P(Args... args) : pair(args...) {} using pair::first; using pair::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; } template P &operator*=(const S &r) { first *= r, second *= r; 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; } template P operator*(const S &r) const { return P(*this) *= r; } P operator-() const { return P{-first, -second}; } }; 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; } vector mkiota(int n) { vector ret(n); iota(begin(ret), end(ret), 0); return ret; } template T mkrev(const T &v) { T w{v}; reverse(begin(w), end(w)); return w; } template bool nxp(vector &v) { return next_permutation(begin(v), end(v)); } // 返り値の型は入力の T に依存 // i 要素目 : [0, a[i]) template vector> product(const vector &a) { vector> ret; vector v; auto dfs = [&](auto rc, int i) -> void { if (i == (int)a.size()) { ret.push_back(v); return; } for (int j = 0; j < a[i]; j++) v.push_back(j), rc(rc, i + 1), v.pop_back(); }; dfs(dfs, 0); return ret; } // F : function(void(T&)), mod を取る操作 // T : 整数型のときはオーバーフローに注意する template T Power(T a, long long n, const T &I, const function &f) { T res = I; for (; n; f(a = a * a), n >>= 1) { if (n & 1) f(res = res * a); } return res; } // T : 整数型のときはオーバーフローに注意する template T Power(T a, long long n, const T &I = T{1}) { return Power(a, n, I, function{[](T &) -> void {}}); } template T Rev(const T &v) { T res = v; reverse(begin(res), end(res)); return res; } template vector Transpose(const vector &v) { using U = typename T::value_type; int H = v.size(), W = v[0].size(); vector res(W, T(H, U{})); for (int i = 0; i < H; i++) { for (int j = 0; j < W; j++) { res[j][i] = v[i][j]; } } return res; } template vector Rotate(const vector &v, int clockwise = true) { using U = typename T::value_type; int H = v.size(), W = v[0].size(); vector res(W, T(H, U{})); for (int i = 0; i < H; i++) { for (int j = 0; j < W; j++) { if (clockwise) { res[W - 1 - j][i] = v[i][j]; } else { res[j][H - 1 - i] = v[i][j]; } } } return res; } } // 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; } istream &operator>>(istream &is, __int128_t &x) { string S; is >> S; x = 0; int flag = 0; for (auto &c : S) { if (c == '-') { flag = true; continue; } x *= 10; x += c - '0'; } if (flag) x = -x; return is; } istream &operator>>(istream &is, __uint128_t &x) { string S; is >> S; x = 0; for (auto &c : S) { x *= 10; x += c - '0'; } return is; } ostream &operator<<(ostream &os, __int128_t x) { if (x == 0) return os << 0; if (x < 0) os << '-', x = -x; string S; while (x) S.push_back('0' + x % 10), x /= 10; reverse(begin(S), end(S)); return os << S; } ostream &operator<<(ostream &os, __uint128_t x) { if (x == 0) return os << 0; string S; while (x) S.push_back('0' + x % 10), x /= 10; reverse(begin(S), end(S)); return os << S; } 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...); } struct IoSetupNya { IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(7); } } iosetupnya; } // namespace Nyaan // debug #ifdef NyaanDebug #define trc(...) (void(0)) #else #define trc(...) (void(0)) #endif #ifdef NyaanLocal #define trc2(...) (void(0)) #else #define trc2(...) (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 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; } // 前 sz 項を取ってくる。sz に足りない項は 0 埋めする FPS pre(int sz) const { FPS ret(begin(*this), begin(*this) + min((int)this->size(), sz)); if ((int)ret.size() < sz) ret.resize(sz); return ret; } 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).empty() && (*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; if (k == 0) { FPS ret(deg); if (deg) ret[0] = 1; return ret; } for (int i = 0; i < n; i++) { if ((*this)[i] != mint(0)) { mint rev = mint(1) / (*this)[i]; FPS ret = (((*this * rev) >> i).log(deg) * k).exp(deg); ret *= (*this)[i].pow(k); ret = (ret << (i * k)).pre(deg); if ((int)ret.size() < deg) ret.resize(deg, mint(0)); return ret; } if (__int128_t(i + 1) * k >= deg) return FPS(deg, mint(0)); } 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 */ namespace poly_gcd { template using FPS = FormalPowerSeries; template using Arr = pair, FPS>; template struct Mat { using fps = FPS; fps a00, a01, a10, a11; Mat() = default; Mat(const fps& a00_, const fps& a01_, const fps& a10_, const fps& a11_) : a00(a00_), a01(a01_), a10(a10_), a11(a11_) {} Mat& operator*=(const Mat& r) { fps A00 = a00 * r.a00 + a01 * r.a10; fps A01 = a00 * r.a01 + a01 * r.a11; fps A10 = a10 * r.a00 + a11 * r.a10; fps A11 = a10 * r.a01 + a11 * r.a11; A00.shrink(); A01.shrink(); A10.shrink(); A11.shrink(); swap(A00, a00); swap(A01, a01); swap(A10, a10); swap(A11, a11); return *this; } static Mat I() { return Mat(fps{mint(1)}, fps(), fps(), fps{mint(1)}); } Mat operator*(const Mat& r) const { return Mat(*this) *= r; } }; template Arr operator*(const Mat& m, const Arr& a) { using fps = FPS; fps b0 = m.a00 * a.first + m.a01 * a.second; fps b1 = m.a10 * a.first + m.a11 * a.second; b0.shrink(); b1.shrink(); return {b0, b1}; }; template void InnerNaiveGCD(Mat& m, Arr& p) { using fps = FPS; fps quo = p.first / p.second; fps rem = p.first - p.second * quo; fps b10 = m.a00 - m.a10 * quo; fps b11 = m.a01 - m.a11 * quo; rem.shrink(); b10.shrink(); b11.shrink(); swap(b10, m.a10); swap(b11, m.a11); swap(b10, m.a00); swap(b11, m.a01); p = {p.second, rem}; } template Mat InnerHalfGCD(Arr p) { int n = p.first.size(), m = p.second.size(); int k = (n + 1) / 2; if (m <= k) return Mat::I(); Mat m1 = InnerHalfGCD(make_pair(p.first >> k, p.second >> k)); p = m1 * p; if ((int)p.second.size() <= k) return m1; InnerNaiveGCD(m1, p); if ((int)p.second.size() <= k) return m1; int l = (int)p.first.size() - 1; int j = 2 * k - l; p.first = p.first >> j; p.second = p.second >> j; return InnerHalfGCD(p) * m1; } template Mat InnerPolyGCD(const FPS& a, const FPS& b) { Arr p{a, b}; p.first.shrink(); p.second.shrink(); int n = p.first.size(), m = p.second.size(); if (n < m) { Mat mat = InnerPolyGCD(p.second, p.first); swap(mat.a00, mat.a01); swap(mat.a10, mat.a11); return mat; } Mat res = Mat::I(); while (1) { Mat m1 = InnerHalfGCD(p); p = m1 * p; if (p.second.empty()) return m1 * res; InnerNaiveGCD(m1, p); if (p.second.empty()) return m1 * res; res = m1 * res; } } template FPS PolyGCD(const FPS& a, const FPS& b) { Arr p(a, b); Mat m = InnerPolyGCD(a, b); p = m * p; if (!p.first.empty()) { mint coeff = p.first.back().inverse(); for (auto& x : p.first) x *= coeff; } return p.first; } template pair> PolyInv(const FPS& f, const FPS& g) { using fps = FPS; pair p(f, g); Mat m = InnerPolyGCD(f, g); fps gcd_ = (m * p).first; if (gcd_.size() != 1) return {false, fps()}; pair x(fps{mint(1)}, g); return {true, ((m * x).first % g) * gcd_[0].inverse()}; } } // namespace poly_gcd using poly_gcd::PolyGCD; using poly_gcd::PolyInv; /** * @brief 多項式GCD * @docs docs/fps/polynomial-gcd.md */ // 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; } /** * @brief グラフテンプレート * @docs docs/graph/graph-template.md */ // 一般のグラフのstからの距離!!!! // unvisited nodes : d = -1 vector Depth(const UnweightedGraph &g, int start = 0) { int n = g.size(); vector ds(n, -1); ds[start] = 0; queue q; q.push(start); while (!q.empty()) { int c = q.front(); q.pop(); int dc = ds[c]; for (auto &d : g[c]) { if (ds[d] == -1) { ds[d] = dc + 1; q.push(d); } } } return ds; } // Depth of Rooted Weighted Tree // unvisited nodes : d = -1 template vector Depth(const WeightedGraph &g, int start = 0) { vector d(g.size(), -1); auto dfs = [&](auto rec, int cur, T val, int par = -1) -> void { d[cur] = val; for (auto &dst : g[cur]) { if (dst == par) continue; rec(rec, dst, val + dst.cost, cur); } }; dfs(dfs, start, 0); return d; } // Diameter of Tree // return value : { {u, v}, length } pair, int> Diameter(const UnweightedGraph &g) { auto d = Depth(g, 0); int u = max_element(begin(d), end(d)) - begin(d); d = Depth(g, u); int v = max_element(begin(d), end(d)) - begin(d); return make_pair(make_pair(u, v), d[v]); } // Diameter of Weighted Tree // return value : { {u, v}, length } template pair, T> Diameter(const WeightedGraph &g) { auto d = Depth(g, 0); int u = max_element(begin(d), end(d)) - begin(d); d = Depth(g, u); int v = max_element(begin(d), end(d)) - begin(d); return make_pair(make_pair(u, v), d[v]); } // nodes on the path u-v ( O(N) ) template vector Path(G &g, int u, int v) { vector ret; int end = 0; auto dfs = [&](auto rec, int cur, int par = -1) -> void { ret.push_back(cur); if (cur == v) { end = 1; return; } for (int dst : g[cur]) { if (dst == par) continue; rec(rec, dst, cur); if (end) return; } if (end) return; ret.pop_back(); }; dfs(dfs, u); return ret; } /** * @brief グラフユーティリティ * @docs docs/graph/graph-utility.md */ template struct has_cost { private: template static auto confirm(U u) -> decltype(u.cost, std::true_type()); static auto confirm(...) -> std::false_type; public: enum : bool { value = decltype(confirm(std::declval()))::value }; }; template vector> inverse_tree(const vector>& g) { int N = (int)g.size(); vector> rg(N); for (int i = 0; i < N; i++) { for (auto& e : g[i]) { if constexpr (is_same::value) { rg[e].push_back(i); } else if constexpr (has_cost::value) { rg[e].emplace_back(e.to, i, e.cost); } else { assert(0); } } } return rg; } template vector> rooted_tree(const vector>& g, int root = 0) { int N = (int)g.size(); vector> rg(N); vector v(N, false); v[root] = true; queue que; que.emplace(root); while (!que.empty()) { auto p = que.front(); que.pop(); for (auto& e : g[p]) { if (v[e] == false) { v[e] = true; que.push(e); rg[p].push_back(e); } } } return rg; } /** * @brief 根付き木・逆辺からなる木への変換 */ template struct HeavyLightDecomposition { private: void dfs_sz(int cur) { size[cur] = 1; for (auto& dst : g[cur]) { if (dst == par[cur]) { if (g[cur].size() >= 2 && int(dst) == int(g[cur][0])) swap(g[cur][0], g[cur][1]); else continue; } depth[dst] = depth[cur] + 1; par[dst] = cur; dfs_sz(dst); size[cur] += size[dst]; if (size[dst] > size[g[cur][0]]) { swap(dst, g[cur][0]); } } } void dfs_hld(int cur) { down[cur] = id++; for (auto dst : g[cur]) { if (dst == par[cur]) continue; nxt[dst] = (int(dst) == int(g[cur][0]) ? nxt[cur] : int(dst)); dfs_hld(dst); } up[cur] = id; } // [u, v) vector> ascend(int u, int v) const { vector> res; while (nxt[u] != nxt[v]) { res.emplace_back(down[u], down[nxt[u]]); u = par[nxt[u]]; } if (u != v) res.emplace_back(down[u], down[v] + 1); return res; } // (u, v] vector> descend(int u, int v) const { if (u == v) return {}; if (nxt[u] == nxt[v]) return {{down[u] + 1, down[v]}}; auto res = descend(u, par[nxt[v]]); res.emplace_back(down[nxt[v]], down[v]); return res; } public: G& g; int id; vector size, depth, down, up, nxt, par; HeavyLightDecomposition(G& _g, int root = 0) : g(_g), id(0), size(g.size(), 0), depth(g.size(), 0), down(g.size(), -1), up(g.size(), -1), nxt(g.size(), root), par(g.size(), root) { dfs_sz(root); dfs_hld(root); } void build(int root) { dfs_sz(root); dfs_hld(root); } pair idx(int i) const { return make_pair(down[i], up[i]); } template void path_query(int u, int v, bool vertex, const F& f) { int l = lca(u, v); for (auto&& [a, b] : ascend(u, l)) { int s = a + 1, t = b; s > t ? f(t, s) : f(s, t); } if (vertex) f(down[l], down[l] + 1); for (auto&& [a, b] : descend(l, v)) { int s = a, t = b + 1; s > t ? f(t, s) : f(s, t); } } template void path_noncommutative_query(int u, int v, bool vertex, const F& f) { int l = lca(u, v); for (auto&& [a, b] : ascend(u, l)) f(a + 1, b); if (vertex) f(down[l], down[l] + 1); for (auto&& [a, b] : descend(l, v)) f(a, b + 1); } template void subtree_query(int u, bool vertex, const F& f) { f(down[u] + int(!vertex), up[u]); } int lca(int a, int b) { while (nxt[a] != nxt[b]) { if (down[a] < down[b]) swap(a, b); a = par[nxt[a]]; } return depth[a] < depth[b] ? a : b; } int dist(int a, int b) { return depth[a] + depth[b] - depth[lca(a, b)] * 2; } }; /** * @brief Heavy Light Decomposition(重軽分解) * @docs docs/tree/heavy-light-decomposition.md */ // template struct fps_fraction { using frac = fps_fraction; using mint = typename fps::value_type; fps p, q; fps_fraction(const fps& numerator = fps{0}, const fps& denominator = fps{1}) : p(numerator), q(denominator) {} friend frac operator+(const frac& l, const frac& r) { return frac{l.p * r.q + r.p * l.q, l.q * r.q}; } friend frac operator-(const frac& l, const frac& r) { return frac{l.p * r.q - r.p * l.q, l.q * r.q}; } friend frac operator*(const frac& l, const frac& r) { return frac{l.p * r.p, l.q * r.q}; } friend frac operator/(const frac& l, const frac& r) { return frac{l.p * r.q, l.q * r.p}; } frac& operator+=(const mint& r) { (*this).p += (*this).q * r; return *this; } frac& operator-=(const mint& r) { (*this).p -= (*this).q * r; return *this; } frac& operator*=(const mint& r) { (*this).p *= r; return *this; } frac operator+(const mint& r) { return frac{*this} += r; } frac operator-(const mint& r) { return frac{*this} -= r; } frac operator*(const mint& r) { return frac{*this} *= r; } frac operator/(const mint& r) { return frac{*this} /= r; } frac& operator+=(const frac& r) { return *this = (*this) + r; } frac& operator-=(const frac& r) { return *this = (*this) - r; } frac& operator*=(const frac& r) { return *this = (*this) * r; } frac operator-() const { return frac{-p, q}; } frac inverse() const { return frac{q, p}; }; void shrink() { p.shrink(), q.shrink(); } friend bool operator==(const frac& l, const frac& r) { return l.p == r.p && l.q == r.q; } friend bool operator!=(const frac& l, const frac& r) { return l.p != r.p || l.q != r.q; } friend ostream& operator<<(ostream& os, const frac& r) { os << "[ "; for (auto& x : r.p) os << x << ", "; os << "], "; os << "[ "; for (auto& x : r.q) os << x << ", "; os << " ]"; return os; } }; template mint LinearRecurrence(long long k, FormalPowerSeries Q, FormalPowerSeries P) { Q.shrink(); mint ret = 0; if (P.size() >= Q.size()) { auto R = P / Q; P -= R * Q; P.shrink(); if (k < (int)R.size()) ret += R[k]; } if ((int)P.size() == 0) return ret; FormalPowerSeries::set_fft(); if (FormalPowerSeries::ntt_ptr == nullptr) { P.resize((int)Q.size() - 1); while (k) { auto Q2 = Q; for (int i = 1; i < (int)Q2.size(); i += 2) Q2[i] = -Q2[i]; auto S = P * Q2; auto T = Q * Q2; if (k & 1) { for (int i = 1; i < (int)S.size(); i += 2) P[i >> 1] = S[i]; for (int i = 0; i < (int)T.size(); i += 2) Q[i >> 1] = T[i]; } else { for (int i = 0; i < (int)S.size(); i += 2) P[i >> 1] = S[i]; for (int i = 0; i < (int)T.size(); i += 2) Q[i >> 1] = T[i]; } k >>= 1; } return ret + P[0]; } else { int N = 1; while (N < (int)Q.size()) N <<= 1; P.resize(2 * N); Q.resize(2 * N); P.ntt(); Q.ntt(); vector S(2 * N), T(2 * N); vector btr(N); for (int i = 0, logn = __builtin_ctz(N); i < (1 << logn); i++) { btr[i] = (btr[i >> 1] >> 1) + ((i & 1) << (logn - 1)); } mint dw = mint(FormalPowerSeries::ntt_pr()) .inverse() .pow((mint::get_mod() - 1) / (2 * N)); while (k) { mint inv2 = mint(2).inverse(); // even degree of Q(x)Q(-x) T.resize(N); for (int i = 0; i < N; i++) T[i] = Q[(i << 1) | 0] * Q[(i << 1) | 1]; S.resize(N); if (k & 1) { // odd degree of P(x)Q(-x) for (auto &i : btr) { S[i] = (P[(i << 1) | 0] * Q[(i << 1) | 1] - P[(i << 1) | 1] * Q[(i << 1) | 0]) * inv2; inv2 *= dw; } } else { // even degree of P(x)Q(-x) for (int i = 0; i < N; i++) { S[i] = (P[(i << 1) | 0] * Q[(i << 1) | 1] + P[(i << 1) | 1] * Q[(i << 1) | 0]) * inv2; } } swap(P, S); swap(Q, T); k >>= 1; if (k < N) break; P.ntt_doubling(); Q.ntt_doubling(); } P.intt(); Q.intt(); return ret + (P * (Q.inv()))[k]; } } template mint kitamasa(long long N, FormalPowerSeries Q, FormalPowerSeries a) { assert(!Q.empty() && Q[0] != 0); if (N < (int)a.size()) return a[N]; assert((int)a.size() >= int(Q.size()) - 1); auto P = a.pre((int)Q.size() - 1) * Q; P.resize(Q.size() - 1); return LinearRecurrence(N, Q, P); } /** * @brief 線形漸化式の高速計算 * @docs docs/fps/kitamasa.md */ using namespace std; // {rank, det(非正方行列の場合は未定義)} を返す // 型が double や Rational でも動くはず?(未検証) // // pivot 候補 : [0, pivot_end) template std::pair GaussElimination(vector> &a, int pivot_end = -1, bool diagonalize = false) { int H = a.size(), W = a[0].size(), rank = 0; if (pivot_end == -1) pivot_end = W; T det = 1; for (int j = 0; j < pivot_end; j++) { int idx = -1; for (int i = rank; i < H; i++) { if (a[i][j] != T(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] != T(1)) { T coeff = T(1) / a[rank][j]; 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] != T(0)) { T 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> inverse_matrix(const vector>& a) { int N = a.size(); assert(N > 0); assert(N == (int)a[0].size()); vector> m(N, vector(2 * N)); for (int i = 0; i < N; i++) { copy(begin(a[i]), end(a[i]), begin(m[i])); m[i][N + i] = 1; } auto [rank, det] = GaussElimination(m, N, true); if (rank != N) return {}; vector> b(N); for (int i = 0; i < N; i++) { copy(begin(m[i]) + N, end(m[i]), back_inserter(b[i])); } return b; } template struct Matrix { vector > A; Matrix() = default; Matrix(int n, int m) : A(n, vector(m, T())) {} Matrix(int n) : A(n, vector(n, T())){}; int H() const { return A.size(); } int W() const { return A[0].size(); } int size() const { return A.size(); } inline const vector &operator[](int k) const { return A[k]; } inline vector &operator[](int k) { return A[k]; } static Matrix I(int n) { Matrix mat(n); for (int i = 0; i < n; i++) mat[i][i] = 1; return (mat); } Matrix &operator+=(const Matrix &B) { int n = H(), m = W(); assert(n == B.H() && m == B.W()); for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) (*this)[i][j] += B[i][j]; return (*this); } Matrix &operator-=(const Matrix &B) { int n = H(), m = W(); assert(n == B.H() && m == B.W()); for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) (*this)[i][j] -= B[i][j]; return (*this); } Matrix &operator*=(const Matrix &B) { int n = H(), m = B.W(), p = W(); assert(p == B.H()); vector > C(n, vector(m, T{})); for (int i = 0; i < n; i++) for (int k = 0; k < p; k++) for (int j = 0; j < m; j++) C[i][j] += (*this)[i][k] * B[k][j]; A.swap(C); return (*this); } Matrix &operator^=(long long k) { Matrix B = Matrix::I(H()); while (k > 0) { if (k & 1) B *= *this; *this *= *this; k >>= 1LL; } A.swap(B.A); return (*this); } Matrix operator+(const Matrix &B) const { return (Matrix(*this) += B); } Matrix operator-(const Matrix &B) const { return (Matrix(*this) -= B); } Matrix operator*(const Matrix &B) const { return (Matrix(*this) *= B); } Matrix operator^(const long long k) const { return (Matrix(*this) ^= k); } bool operator==(const Matrix &B) const { assert(H() == B.H() && W() == B.W()); for (int i = 0; i < H(); i++) for (int j = 0; j < W(); j++) if (A[i][j] != B[i][j]) return false; return true; } bool operator!=(const Matrix &B) const { assert(H() == B.H() && W() == B.W()); for (int i = 0; i < H(); i++) for (int j = 0; j < W(); j++) if (A[i][j] != B[i][j]) return true; return false; } Matrix inverse() const { assert(H() == W()); Matrix B(H()); B.A = inverse_matrix(A); return B; } friend ostream &operator<<(ostream &os, const Matrix &p) { int n = p.H(), m = p.W(); for (int i = 0; i < n; i++) { os << (i ? " " : "") << "["; for (int j = 0; j < m; j++) { os << p[i][j] << (j + 1 == m ? "]\n" : ","); } } return (os); } T determinant() const { Matrix B(*this); assert(H() == W()); T ret = 1; for (int i = 0; i < H(); i++) { int idx = -1; for (int j = i; j < W(); j++) { if (B[j][i] != 0) { idx = j; break; } } if (idx == -1) return 0; if (i != idx) { ret *= T(-1); swap(B[i], B[idx]); } ret *= B[i][i]; T inv = T(1) / B[i][i]; for (int j = 0; j < W(); j++) { B[i][j] *= inv; } for (int j = i + 1; j < H(); j++) { T a = B[j][i]; if (a == 0) continue; for (int k = i; k < W(); k++) { B[j][k] -= B[i][k] * a; } } } return ret; } }; /** * @brief 行列ライブラリ */ // template struct NTT { static constexpr uint32_t get_pr() { uint32_t _mod = mint::get_mod(); using u64 = uint64_t; u64 ds[32] = {}; int idx = 0; u64 m = _mod - 1; for (u64 i = 2; i * i <= m; ++i) { if (m % i == 0) { ds[idx++] = i; while (m % i == 0) m /= i; } } if (m != 1) ds[idx++] = m; uint32_t _pr = 2; while (1) { int flg = 1; for (int i = 0; i < idx; ++i) { u64 a = _pr, b = (_mod - 1) / ds[i], r = 1; while (b) { if (b & 1) r = r * a % _mod; a = a * a % _mod; b >>= 1; } if (r == 1) { flg = 0; break; } } if (flg == 1) break; ++_pr; } return _pr; }; static constexpr uint32_t mod = mint::get_mod(); static constexpr uint32_t pr = get_pr(); static constexpr int level = __builtin_ctzll(mod - 1); mint dw[level], dy[level]; void setwy(int k) { mint w[level], y[level]; w[k - 1] = mint(pr).pow((mod - 1) / (1 << k)); y[k - 1] = w[k - 1].inverse(); for (int i = k - 2; i > 0; --i) w[i] = w[i + 1] * w[i + 1], y[i] = y[i + 1] * y[i + 1]; dw[1] = w[1], dy[1] = y[1], dw[2] = w[2], dy[2] = y[2]; for (int i = 3; i < k; ++i) { dw[i] = dw[i - 1] * y[i - 2] * w[i]; dy[i] = dy[i - 1] * w[i - 2] * y[i]; } } NTT() { setwy(level); } void fft4(vector &a, int k) { if ((int)a.size() <= 1) return; if (k == 1) { mint a1 = a[1]; a[1] = a[0] - a[1]; a[0] = a[0] + a1; return; } if (k & 1) { int v = 1 << (k - 1); for (int j = 0; j < v; ++j) { mint ajv = a[j + v]; a[j + v] = a[j] - ajv; a[j] += ajv; } } int u = 1 << (2 + (k & 1)); int v = 1 << (k - 2 - (k & 1)); mint one = mint(1); mint imag = dw[1]; while (v) { // jh = 0 { int j0 = 0; int j1 = v; int j2 = j1 + v; int j3 = j2 + v; for (; j0 < v; ++j0, ++j1, ++j2, ++j3) { mint t0 = a[j0], t1 = a[j1], t2 = a[j2], t3 = a[j3]; mint t0p2 = t0 + t2, t1p3 = t1 + t3; mint t0m2 = t0 - t2, t1m3 = (t1 - t3) * imag; a[j0] = t0p2 + t1p3, a[j1] = t0p2 - t1p3; a[j2] = t0m2 + t1m3, a[j3] = t0m2 - t1m3; } } // jh >= 1 mint ww = one, xx = one * dw[2], wx = one; for (int jh = 4; jh < u;) { ww = xx * xx, wx = ww * xx; int j0 = jh * v; int je = j0 + v; int j2 = je + v; for (; j0 < je; ++j0, ++j2) { mint t0 = a[j0], t1 = a[j0 + v] * xx, t2 = a[j2] * ww, t3 = a[j2 + v] * wx; mint t0p2 = t0 + t2, t1p3 = t1 + t3; mint t0m2 = t0 - t2, t1m3 = (t1 - t3) * imag; a[j0] = t0p2 + t1p3, a[j0 + v] = t0p2 - t1p3; a[j2] = t0m2 + t1m3, a[j2 + v] = t0m2 - t1m3; } xx *= dw[__builtin_ctzll((jh += 4))]; } u <<= 2; v >>= 2; } } void ifft4(vector &a, int k) { if ((int)a.size() <= 1) return; if (k == 1) { mint a1 = a[1]; a[1] = a[0] - a[1]; a[0] = a[0] + a1; return; } int u = 1 << (k - 2); int v = 1; mint one = mint(1); mint imag = dy[1]; while (u) { // jh = 0 { int j0 = 0; int j1 = v; int j2 = v + v; int j3 = j2 + v; for (; j0 < v; ++j0, ++j1, ++j2, ++j3) { mint t0 = a[j0], t1 = a[j1], t2 = a[j2], t3 = a[j3]; mint t0p1 = t0 + t1, t2p3 = t2 + t3; mint t0m1 = t0 - t1, t2m3 = (t2 - t3) * imag; a[j0] = t0p1 + t2p3, a[j2] = t0p1 - t2p3; a[j1] = t0m1 + t2m3, a[j3] = t0m1 - t2m3; } } // jh >= 1 mint ww = one, xx = one * dy[2], yy = one; u <<= 2; for (int jh = 4; jh < u;) { ww = xx * xx, yy = xx * imag; int j0 = jh * v; int je = j0 + v; int j2 = je + v; for (; j0 < je; ++j0, ++j2) { mint t0 = a[j0], t1 = a[j0 + v], t2 = a[j2], t3 = a[j2 + v]; mint t0p1 = t0 + t1, t2p3 = t2 + t3; mint t0m1 = (t0 - t1) * xx, t2m3 = (t2 - t3) * yy; a[j0] = t0p1 + t2p3, a[j2] = (t0p1 - t2p3) * ww; a[j0 + v] = t0m1 + t2m3, a[j2 + v] = (t0m1 - t2m3) * ww; } xx *= dy[__builtin_ctzll(jh += 4)]; } u >>= 4; v <<= 2; } if (k & 1) { u = 1 << (k - 1); for (int j = 0; j < u; ++j) { mint ajv = a[j] - a[j + u]; a[j] += a[j + u]; a[j + u] = ajv; } } } void ntt(vector &a) { if ((int)a.size() <= 1) return; fft4(a, __builtin_ctz(a.size())); } void intt(vector &a) { if ((int)a.size() <= 1) return; ifft4(a, __builtin_ctz(a.size())); mint iv = mint(a.size()).inverse(); for (auto &x : a) x *= iv; } vector multiply(const vector &a, const vector &b) { int l = a.size() + b.size() - 1; if (min(a.size(), b.size()) <= 40) { vector s(l); for (int i = 0; i < (int)a.size(); ++i) for (int j = 0; j < (int)b.size(); ++j) s[i + j] += a[i] * b[j]; return s; } int k = 2, M = 4; while (M < l) M <<= 1, ++k; setwy(k); vector s(M); for (int i = 0; i < (int)a.size(); ++i) s[i] = a[i]; fft4(s, k); if (a.size() == b.size() && a == b) { for (int i = 0; i < M; ++i) s[i] *= s[i]; } else { vector t(M); for (int i = 0; i < (int)b.size(); ++i) t[i] = b[i]; fft4(t, k); for (int i = 0; i < M; ++i) s[i] *= t[i]; } ifft4(s, k); s.resize(l); mint invm = mint(M).inverse(); for (int i = 0; i < l; ++i) s[i] *= invm; return s; } void ntt_doubling(vector &a) { int M = (int)a.size(); auto b = a; intt(b); mint r = 1, zeta = mint(pr).pow((mint::get_mod() - 1) / (M << 1)); for (int i = 0; i < M; i++) b[i] *= r, r *= zeta; ntt(b); copy(begin(b), end(b), back_inserter(a)); } }; template void FormalPowerSeries::set_fft() { if (!ntt_ptr) ntt_ptr = new NTT; } template FormalPowerSeries& FormalPowerSeries::operator*=( const FormalPowerSeries& r) { if (this->empty() || r.empty()) { this->clear(); return *this; } set_fft(); auto ret = static_cast*>(ntt_ptr)->multiply(*this, r); return *this = FormalPowerSeries(ret.begin(), ret.end()); } template void FormalPowerSeries::ntt() { set_fft(); static_cast*>(ntt_ptr)->ntt(*this); } template void FormalPowerSeries::intt() { set_fft(); static_cast*>(ntt_ptr)->intt(*this); } template void FormalPowerSeries::ntt_doubling() { set_fft(); static_cast*>(ntt_ptr)->ntt_doubling(*this); } template int FormalPowerSeries::ntt_pr() { set_fft(); return static_cast*>(ntt_ptr)->pr; } template FormalPowerSeries FormalPowerSeries::inv(int deg) const { assert((*this)[0] != mint(0)); if (deg == -1) deg = (int)this->size(); FormalPowerSeries res(deg); res[0] = {mint(1) / (*this)[0]}; for (int d = 1; d < deg; d <<= 1) { FormalPowerSeries f(2 * d), g(2 * d); for (int j = 0; j < min((int)this->size(), 2 * d); j++) f[j] = (*this)[j]; for (int j = 0; j < d; j++) g[j] = res[j]; f.ntt(); g.ntt(); for (int j = 0; j < 2 * d; j++) f[j] *= g[j]; f.intt(); for (int j = 0; j < d; j++) f[j] = 0; f.ntt(); for (int j = 0; j < 2 * d; j++) f[j] *= g[j]; f.intt(); for (int j = d; j < min(2 * d, deg); j++) res[j] = -f[j]; } return res.pre(deg); } template FormalPowerSeries FormalPowerSeries::exp(int deg) const { using fps = FormalPowerSeries; assert((*this).size() == 0 || (*this)[0] == mint(0)); if (deg == -1) deg = this->size(); fps inv; inv.reserve(deg + 1); inv.push_back(mint(0)); inv.push_back(mint(1)); auto inplace_integral = [&](fps& F) -> void { const int n = (int)F.size(); auto mod = mint::get_mod(); while ((int)inv.size() <= n) { int i = inv.size(); inv.push_back((-inv[mod % i]) * (mod / i)); } F.insert(begin(F), mint(0)); for (int i = 1; i <= n; i++) F[i] *= inv[i]; }; auto inplace_diff = [](fps& F) -> void { if (F.empty()) return; F.erase(begin(F)); mint coeff = 1, one = 1; for (int i = 0; i < (int)F.size(); i++) { F[i] *= coeff; coeff += one; } }; fps b{1, 1 < (int)this->size() ? (*this)[1] : 0}, c{1}, z1, z2{1, 1}; for (int m = 2; m < deg; m *= 2) { auto y = b; y.resize(2 * m); y.ntt(); z1 = z2; fps z(m); for (int i = 0; i < m; ++i) z[i] = y[i] * z1[i]; z.intt(); fill(begin(z), begin(z) + m / 2, mint(0)); z.ntt(); for (int i = 0; i < m; ++i) z[i] *= -z1[i]; z.intt(); c.insert(end(c), begin(z) + m / 2, end(z)); z2 = c; z2.resize(2 * m); z2.ntt(); fps x(begin(*this), begin(*this) + min(this->size(), m)); x.resize(m); inplace_diff(x); x.push_back(mint(0)); x.ntt(); for (int i = 0; i < m; ++i) x[i] *= y[i]; x.intt(); x -= b.diff(); x.resize(2 * m); for (int i = 0; i < m - 1; ++i) x[m + i] = x[i], x[i] = mint(0); x.ntt(); for (int i = 0; i < 2 * m; ++i) x[i] *= z2[i]; x.intt(); x.pop_back(); inplace_integral(x); for (int i = m; i < min(this->size(), 2 * m); ++i) x[i] += (*this)[i]; fill(begin(x), begin(x) + m, mint(0)); x.ntt(); for (int i = 0; i < 2 * m; ++i) x[i] *= y[i]; x.intt(); b.insert(end(b), begin(x) + m, end(x)); } return fps{begin(b), begin(b) + deg}; } /** * @brief NTT mod用FPSライブラリ * @docs docs/fps/ntt-friendly-fps.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(mod < (1 << 30), "invalid, mod >= 2 ^ 30"); static_assert((mod & 1) == 1, "invalid, mod % 2 == 0"); static_assert(r * mod == 1, "this code has bugs."); 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 operator+() const { return 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 { int x = get(), y = mod, u = 1, v = 0, t = 0, tmp = 0; while (y > 0) { t = x / y; x -= t * y, u -= t * v; tmp = x, x = y, y = tmp; tmp = u, u = v, v = tmp; } return mint{u}; } 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; } }; using namespace std; // コンストラクタの MAX に 「C(n, r) や fac(n) でクエリを投げる最大の n 」 // を入れると倍速くらいになる // mod を超えて前計算して 0 割りを踏むバグは対策済み template struct Binomial { vector f, g, h; Binomial(int MAX = 0) { assert(T::get_mod() != 0 && "Binomial()"); f.resize(1, T{1}); g.resize(1, T{1}); h.resize(1, T{1}); if (MAX > 0) extend(MAX + 1); } void extend(int m = -1) { int n = f.size(); if (m == -1) m = n * 2; m = min(m, T::get_mod()); if (n >= m) return; 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); } // [x^r] 1 / (1-x)^n T H(int n, int r) { if (n < 0 || r < 0) return T(0); return r == 0 ? 1 : C(n + r - 1, r); } }; // #include "fps/arbitrary-fps.hpp" // using namespace Nyaan; using mint = LazyMontgomeryModInt<998244353>; // using mint = LazyMontgomeryModInt<1000000007>; using vm = vector; using vvm = vector; Binomial C; using fps = FormalPowerSeries; using namespace Nyaan; using frac = fps_fraction; using Mat = Matrix; /* void shrink(frac& prod) { auto gc = PolyGCD(prod.p, prod.q); gc *= gc[0].inverse(); prod.p /= gc; prod.q /= gc; prod.p.shrink(); prod.q.shrink(); } // これを高速化 mint naive(int N, int M, int S, int T, vvi g) { V dp(N); auto dfs = [&](auto rc, int c, int p) -> frac { frac s; each(d, g[c]) { if (d == p) continue; rc(rc, d, c); s += dp[d]; } s = fps{1, -1} - s * fps{0, 0, 1}; swap(s.p, s.q); return dp[c] = s; }; dfs(dfs, T, -1); rep(i, N) trc(dp[i]); auto path = Path(g, S, T); if (sz(path) - 1 > M) return 0; frac prod = fps{1}; each(p, path) prod *= dp[p]; trc(prod); // fps f = prod.p * (prod.q.inv(M + 10)); return LinearRecurrence(M - (sz(path) - 1), prod.q, prod.p); } */ vvi g2; frac light(int c); V heavy(int c) { if (g2[c].empty()) return V{frac{fps{0}, fps{1}}}; vector v, res = heavy(g2[c][0]); v.push_back(frac{fps{0}, fps{1}}); rep1(i, sz(g2[c]) - 1) v.push_back(light(g2[c][i])); while (v.size() >= 2u) { vector w; for (int i = 0; i + 1 < (int)v.size(); i += 2) w.push_back(v[i] + v[i + 1]); if (v.size() & 1) w.push_back(v.back()); swap(v, w); } res.push_back(v.back()); return res; } frac light(int c) { auto v = heavy(c); Mat I(2); I[0][0] = I[1][1] = fps{1}; Mat oya(2); oya[0][1] = fps{1}; oya[1][0] = fps{0, 0, -1}; oya[1][1] = fps{1, -1}; V ms{I, I}; each(f, v) { Mat m(2); m[0][0] = m[1][1] = f.q; m[0][1] = f.p; ms.push_back(m); ms.push_back(oya); } reverse(all(ms)); while (sz(ms) >= 2) { V nx; for (int i = 0; i + 1 < sz(ms); i += 2) nx.push_back(ms[i] * ms[i + 1]); if (sz(ms) % 2) nx.push_back(ms.back()); ms = nx; } auto m = ms[0]; fps p = m[0][1]; fps q = m[1][1]; return frac{p, q}; } mint calc(int N, int M, int S, int T, vvi g) { auto path = Path(g, S, T); g = rooted_tree(g, T); HeavyLightDecomposition hld{g}; if (sz(path) - 1 > M) return 0; { set pathset; each(p, path) pathset.insert(p); g2.resize(N); rep(i, N) each(j, g[i]) { if (pathset.count(j) == 0) g2[i].push_back(j); } } // S, ..., T について問題を解く V dp(sz(path)); rep(j, sz(path)) { int c = path[j]; V v; v.push_back(frac{fps{0}, fps{1}}); rep(i, sz(g2[c])) v.push_back(light(g2[c][i])); while (v.size() >= 2u) { vector w; for (int i = 0; i + 1 < (int)v.size(); i += 2) w.push_back(v[i] + v[i + 1]); if (v.size() & 1) w.push_back(v.back()); swap(v, w); } dp[j] = v[0]; dp[j].p.shrink(); dp[j].q.shrink(); } /* // 一旦愚直を書く frac prod{fps{1}, fps{1}}; { frac s{fps{0}, fps{1}}; each(x, dp) { s += x; s = fps{1, -1} - s * fps{0, 0, 1}; swap(s.p, s.q); prod *= s; } } return LinearRecurrence(M - (sz(path) - 1), prod.q, prod.p); */ exit(1); frac fs = fps{1, -1} - dp[0] * fps{0, 0, 1}; swap(fs.p, fs.q); using Mat2 = Matrix; V ms; { Mat2 m(2); m[0][0] = m[1][1] = frac{fps{1}, fps{1}}; ms.push_back(m); } rep1(i, sz(path) - 1) { Mat2 m(2); m[0][1] = fps{1}; m[1][0] = fps{0, 0, -1}; m[1][1] = fps{1, -1} - dp[i] * fps{0, 0, 1}; ms.push_back(m); } reverse(all(ms)); while (sz(ms) >= 2) { V nx; for (int i = 0; i + 1 < sz(ms); i += 2) nx.push_back(ms[i] * ms[i + 1]); if (sz(ms) % 2) nx.push_back(ms.back()); ms = nx; } auto m = ms[0]; frac ftp = fs.p * m[0][0] + fs.q * m[0][1]; frac ftq = fs.p * m[1][0] + fs.q * m[1][1]; trc(ftp, ftq); frac f = fs.p / ftq; trc(f); return LinearRecurrence(M - (sz(path) - 1), f.q, f.p); } void q() { ini(N, M, S, T); auto g = graph(N); S--, T--; // out(naive(N, M, S, T, g)); out(calc(N, M, S, T, g)); } void Nyaan::solve() { int t = 1; // in(t); while (t--) q(); }