#define _USE_MATH_DEFINES #include using namespace std; #define FOR(i,m,n) for(int i=(m);i<(n);++i) #define REP(i,n) FOR(i,0,n) #define ALL(v) (v).begin(),(v).end() using ll = long long; constexpr int INF = 0x3f3f3f3f; constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL; constexpr double EPS = 1e-8; constexpr int MOD = 1000000007; // constexpr int MOD = 998244353; constexpr int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1}; constexpr int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1}; template inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; } template inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; } struct IOSetup { IOSetup() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << fixed << setprecision(20); } } iosetup; template struct MInt { unsigned int val; MInt(): val(0) {} MInt(long long x) : val(x >= 0 ? x % M : x % M + M) {} static constexpr int get_mod() { return M; } static void set_mod(int divisor) { assert(divisor == M); } static void init(int x = 10000000) { inv(x, true); fact(x); fact_inv(x); } static MInt inv(int x, bool init = false) { // assert(0 <= x && x < M && std::__gcd(x, M) == 1); static std::vector inverse{0, 1}; int prev = inverse.size(); if (init && x >= prev) { // "x!" and "M" must be disjoint. inverse.resize(x + 1); for (int i = prev; i <= x; ++i) inverse[i] = -inverse[M % i] * (M / i); } if (x < inverse.size()) return inverse[x]; unsigned int a = x, b = M; int u = 1, v = 0; while (b) { unsigned int q = a / b; std::swap(a -= q * b, b); std::swap(u -= q * v, v); } return u; } static MInt fact(int x) { static std::vector f{1}; int prev = f.size(); if (x >= prev) { f.resize(x + 1); for (int i = prev; i <= x; ++i) f[i] = f[i - 1] * i; } return f[x]; } static MInt fact_inv(int x) { static std::vector finv{1}; int prev = finv.size(); if (x >= prev) { finv.resize(x + 1); finv[x] = inv(fact(x).val); for (int i = x; i > prev; --i) finv[i - 1] = finv[i] * i; } return finv[x]; } static MInt nCk(int n, int k) { if (n < 0 || n < k || k < 0) return 0; if (n - k > k) k = n - k; return fact(n) * fact_inv(k) * fact_inv(n - k); } static MInt nPk(int n, int k) { return n < 0 || n < k || k < 0 ? 0 : fact(n) * fact_inv(n - k); } static MInt nHk(int n, int k) { return n < 0 || k < 0 ? 0 : (k == 0 ? 1 : nCk(n + k - 1, k)); } static MInt large_nCk(long long n, int k) { if (n < 0 || n < k || k < 0) return 0; inv(k, true); MInt res = 1; for (int i = 1; i <= k; ++i) res *= inv(i) * n--; return res; } MInt pow(long long exponent) const { MInt tmp = *this, res = 1; while (exponent > 0) { if (exponent & 1) res *= tmp; tmp *= tmp; exponent >>= 1; } return res; } MInt &operator+=(const MInt &x) { if((val += x.val) >= M) val -= M; return *this; } MInt &operator-=(const MInt &x) { if((val += M - x.val) >= M) val -= M; return *this; } MInt &operator*=(const MInt &x) { val = static_cast(val) * x.val % M; return *this; } MInt &operator/=(const MInt &x) { return *this *= inv(x.val); } bool operator==(const MInt &x) const { return val == x.val; } bool operator!=(const MInt &x) const { return val != x.val; } bool operator<(const MInt &x) const { return val < x.val; } bool operator<=(const MInt &x) const { return val <= x.val; } bool operator>(const MInt &x) const { return val > x.val; } bool operator>=(const MInt &x) const { return val >= x.val; } MInt &operator++() { if (++val == M) val = 0; return *this; } MInt operator++(int) { MInt res = *this; ++*this; return res; } MInt &operator--() { val = (val == 0 ? M : val) - 1; return *this; } MInt operator--(int) { MInt res = *this; --*this; return res; } MInt operator+() const { return *this; } MInt operator-() const { return MInt(val ? M - val : 0); } MInt operator+(const MInt &x) const { return MInt(*this) += x; } MInt operator-(const MInt &x) const { return MInt(*this) -= x; } MInt operator*(const MInt &x) const { return MInt(*this) *= x; } MInt operator/(const MInt &x) const { return MInt(*this) /= x; } friend std::ostream &operator<<(std::ostream &os, const MInt &x) { return os << x.val; } friend std::istream &operator>>(std::istream &is, MInt &x) { long long val; is >> val; x = MInt(val); return is; } }; namespace std { template MInt abs(const MInt &x) { return x; } } using ModInt = MInt; struct UnionFind { UnionFind(int n) : data(n, -1) {} int root(int ver) { return data[ver] < 0 ? ver : data[ver] = root(data[ver]); } bool unite(int u, int v) { u = root(u); v = root(v); if (u == v) return false; if (data[u] > data[v]) std::swap(u, v); data[u] += data[v]; data[v] = u; return true; } bool same(int u, int v) { return root(u) == root(v); } int size(int ver) { return -data[root(ver)]; } private: std::vector data; }; template struct Matrix { Matrix(int m, int n, T val = 0) : dat(m, std::vector(n, val)) {} int height() const { return dat.size(); } int width() const { return dat.front().size(); } Matrix pow(long long exponent) const { int n = height(); Matrix tmp = *this, res(n, n, 0); for (int i = 0; i < n; ++i) res[i][i] = 1; while (exponent > 0) { if (exponent & 1) res *= tmp; tmp *= tmp; exponent >>= 1; } return res; } inline const std::vector &operator[](const int idx) const { return dat[idx]; } inline std::vector &operator[](const int idx) { return dat[idx]; } Matrix &operator=(const Matrix &x) { int m = x.height(), n = x.width(); dat.resize(m, std::vector(n)); for (int i = 0; i < m; ++i) for (int j = 0; j < n; ++j) dat[i][j] = x[i][j]; return *this; } Matrix &operator+=(const Matrix &x) { int m = height(), n = width(); for (int i = 0; i < m; ++i) for (int j = 0; j < n; ++j) dat[i][j] += x[i][j]; return *this; } Matrix &operator-=(const Matrix &x) { int m = height(), n = width(); for (int i = 0; i < m; ++i) for (int j = 0; j < n; ++j) dat[i][j] -= x[i][j]; return *this; } Matrix &operator*=(const Matrix &x) { int m = height(), n = x.width(), l = width(); std::vector> res(m, std::vector(n, 0)); for (int i = 0; i < m; ++i) for (int j = 0; j < n; ++j) { for (int k = 0; k < l; ++k) res[i][j] += dat[i][k] * x[k][j]; } std::swap(dat, res); return *this; } Matrix operator+(const Matrix &x) const { return Matrix(*this) += x; } Matrix operator-(const Matrix &x) const { return Matrix(*this) -= x; } Matrix operator*(const Matrix &x) const { return Matrix(*this) *= x; } private: std::vector> dat; }; template T kita_masa(const std::vector &c, const std::vector &a, long long n) { if (n == 0) return a[0]; int k = c.size(); std::vector coefficient[3]; for (int i = 0; i < 3; ++i) coefficient[i].assign(k, 0); if (k == 1) { coefficient[0][0] = c[0] * a[0]; } else { coefficient[0][1] = 1; } auto succ = [&c, k, &coefficient]() -> void { for (int i = 0; i < k - 1; ++i) coefficient[0][i] += coefficient[0].back() * c[i + 1]; coefficient[0].back() *= c[0]; std::rotate(coefficient[0].begin(), coefficient[0].begin() + k - 1, coefficient[0].end()); }; for (int bit = 62 - __builtin_clzll(n); bit >= 0; --bit) { for (int i = 1; i < 3; ++i) std::copy(coefficient[0].begin(), coefficient[0].end(), coefficient[i].begin()); for (T &e : coefficient[1]) e *= coefficient[2][0]; for (int i = 1; i < k; ++i) { succ(); for (int j = 0; j < k; ++j) coefficient[1][j] += coefficient[2][i] * coefficient[0][j]; } coefficient[0].swap(coefficient[1]); if (n >> bit & 1) succ(); } T res = 0; for (int i = 0; i < k; ++i) res += coefficient[0][i] * a[i]; return res; } // https://github.com/beet-aizu/library/blob/bca52958e61426377b8f56817d63f912070b3487/polynomial/berlekampmassey.cpp template vector berlekamp_massey(vector &as){ using Poly = vector; int n=as.size(); Poly bs({-T(1)}),cs({-T(1)}); T y(1); for(int ed=1;ed<=n;ed++){ int l=cs.size(),m=bs.size(); T x(0); for(int i=0;i> n >> m; int size = 2; map, int> mp; mp[vector(n, -1)] = 0; vector> reach(size); vector finish{false, true}; queue> que({vector(n, -1)}); while (!que.empty()) { vector prev = que.front(); que.pop(); int id = mp[prev]; if (id > 0) { bool is_con = true; int only = *max_element(ALL(prev)); REP(i, n) is_con &= prev[i] == -1 || prev[i] == only; if (is_con) reach[id].emplace_back(1); } FOR(b, 1, 1 << n) { UnionFind uf(n * 2); REP(i, n) { if (prev[i] == -1) continue; FOR(j, i + 1, n) { if (prev[j] == prev[i]) uf.unite(i, j); } } FOR(i, 1, n) { if ((b >> (i - 1) & 1) && (b >> i & 1)) uf.unite(n + i - 1, n + i); } REP(i, n) { if (prev[i] != -1 && (b >> i & 1)) uf.unite(i, n + i); } vector nx(n, -1); map root; REP(i, n) { if (b >> i & 1) { int rt = uf.root(n + i); if (root.count(rt) == 0) { int tmp = root.size(); root[rt] = tmp; } nx[i] = root[rt]; } } bool is_con = true; REP(i, n) is_con &= prev[i] == -1 || root.count(uf.root(i)) == 1; if (is_con) { if (mp.count(nx) == 0) { mp[nx] = size++; que.emplace(nx); reach.emplace_back(); finish.emplace_back(root.size() == 1); } reach[id].emplace_back(mp[nx]); } } } vector dp(size, 0), a; dp[0] = 1; while (a.size() < size) { vector nx(size, 0); nx[0] += dp[0]; nx[1] += dp[1]; REP(i, size) for (int j : reach[i]) nx[j] += dp[i]; dp.swap(nx); a.emplace_back(0); REP(i, size) { if (finish[i]) a.back() += dp[i]; } } cout << kita_masa(berlekamp_massey(a), a, m - 1) << '\n'; return 0; }