#line 1 "playspace/main.cpp" #include #line 3 "library/gandalfr/math/matrix.hpp" #line 8 "library/gandalfr/math/matrix.hpp" template class matrix { private: int H, W; std::valarray> table; enum rowtrans_operation_name { SCALE, SWAP, ADD }; struct rowtrans_operation { int op, tar, res; T scl; }; using operations_history = std::vector; public: matrix() = default; matrix(int _H, int _W, T val = 0) : H(_H), W(_W), table(std::valarray(val, _W), _H) {} matrix(const std::vector> &vv) : H(vv.size()), W(vv[0].size()), table(std::valarray(W), H) { for (int i = 0; i < H; i++) for (int j = 0; j < W; j++) table[i][j] = vv[i][j]; } matrix(const std::valarray> &vv) : H(vv.size()), W(vv[0].size()), table(vv) {} /** * @brief 行列をリサイズする。 * @param val 拡張部分の値 */ void resize(int _H, int _W, T val = 0) { H = _H, W = _W; table.resize(_H, std::valarray(val, _H)); } int size_H() const { return H; } int size_W() const { return W; } void transpose() { matrix ret(W, H); for (int i = 0; i < H; i++) for (int j = 0; j < W; j++) ret.table[j][i] = table[i][j]; *this = ret; } /** * @brief 第 i 行に対して行単位で代入を行う * @example A.row_assign(3, {1,2,3}); */ void row_assign(int i, const std::valarray &row) { assert(0 <= i && i < H); assert(W == (int)row.size()); table[i] = row; } /** * @brief 第 i 行, 第 j 行を入れ替える */ void row_swap(int i, int j) { assert(0 <= i && i < H); assert(0 <= j && j < H); table[i].swap(table[j]); } /** * @attention O(n^3) * @attention 整数型では正しく計算できない。double や fraction を使うこと。 * @attention 枢軸選びをしていないので double では誤差が出るかも。 */ operations_history sweep_method() { operations_history hist; for (int h = 0, w = 0; h < H && w < W; w++) { if (table[h][w] == 0) { for (int piv = h + 1; piv < H; piv++) { if (table[piv][w] != 0) { hist.push_back({SWAP, h, piv, 0}); row_swap(h, piv); break; } } if (table[h][w] == 0) { continue; } } T inv = 1 / table[h][w]; hist.push_back({SCALE, -1, w, inv}); table[h] *= inv; for (int j = h + 1; j < H; j++) { hist.push_back({ADD, h, j, -table[j][w]}); table[j] -= table[h] * table[j][w]; } h++; } return hist; } int rank() const { auto U(*this); U.sweep_method(); int r = 0; for (int i = 0; i < H; ++i) { for (int j = i; j < W; ++j) { if (U.table[i][j] != 0) { r++; break; } } } return r; } T determinant() const { assert(H == W); matrix U(*this); T det = 1; auto hist = U.sweep_method(); if (U.table[H - 1][H - 1] == 0) return 0; for (auto &[op, tar, res, scl] : hist) { switch (op) { case SCALE: det /= scl; break; case SWAP: det *= -1; break; } } return det; } std::vector solve_system_of_equations(const std::vector &y) { assert(H == W); std::vector x(y); matrix U(*this); auto hist = U.sweep_method(); if (U.table[H - 1][H - 1] == 0) return {}; for (auto &[op, tar, res, scl] : hist) { switch (op) { case SCALE: x[res] *= scl; break; case SWAP: std::swap(x[tar], x[res]); break; case ADD: x[res] += x[tar] * scl; break; } } for (int i = H - 1; i >= 0; --i) { for (int j = 0; j < i; ++j) { x[j] -= U.table[j][i] * x[i]; } } return x; } matrix inverse() const { assert(H == W); matrix INV(matrix::E(H)), U(*this); auto hist = U.sweep_method(); if (U.table[H - 1][H - 1] == 0) return matrix(0, 0); for (auto &[op, tar, res, scl] : hist) { switch (op) { case SCALE: INV.table[res] *= scl; break; case SWAP: std::swap(INV.table[tar], INV.table[res]); break; case ADD: INV.table[res] += INV.table[tar] * scl; break; } } for (int i = H - 1; i >= 0; --i) { for (int j = 0; j < i; ++j) { INV.table[j] -= INV.table[i] * U.table[j][i]; } } return INV; } void print() const { for (int i = 0; i < H; i++) { for (int j = 0; j < W; j++) { std::cout << table[i][j] << (j == W - 1 ? "" : " "); } std::cout << std::endl; } } matrix &operator+=(const matrix &a) { this->table += a.table; return *this; } matrix &operator-=(const matrix &a) { this->table -= a.table; return *this; } matrix &operator*=(const T &a) { this->table *= a; return *this; } matrix &operator*=(const matrix &a) { assert(W == a.H); matrix a_t(a), ret(H, a.W); a_t.transpose(); for (int i = 0; i < H; i++) { for (int j = 0; j < a_t.H; j++) { ret.table[i][j] = (table[i] * a_t.table[j]).sum(); } } return *this = ret; } matrix &operator/=(const T &a) { this->table /= a; return *this; } /** * @brief 行列の冪乗。 * @param n 指数 * @attention n が 0 なら単位行列。 * @attention 演算子の優先度に注意。 */ matrix operator^=(long long n) { assert(H == W); if (n == 0) return *this = E(H); n--; matrix x(*this); while (n) { if (n & 1) *this *= x; x *= x; n >>= 1; } return *this; } matrix operator+() const { return *this; } matrix operator-() const { return matrix(*this) *= -1; } matrix operator+(const matrix &a) const { return matrix(*this) += a; } matrix operator-(const matrix &a) const { return matrix(*this) -= a; } matrix operator*(const T &a) { return matrix(*this) *= a; } matrix operator*(const matrix &a) const { return matrix(*this) *= a; } matrix operator/(const T &a) const { return matrix(*this) /= a; } matrix operator^(long long n) const { return matrix(*this) ^= n; } friend std::istream &operator>>(std::istream &is, matrix &mt) { for (auto &arr : mt.table) for (auto &x : arr) is >> x; return is; } const T &operator()(int h, int w) const { assert(0 <= h && h < H && 0 <= w && w <= W); return table[h][w]; } T &operator()(int h, int w) { assert(0 <= h && h < H && 0 <= w && w <= W); return table[h][w]; } template bool operator==(const matrix &other) { if (size_H() != other.size_H() || size_W() != other.size_W()) return false; for (int h = 0; h < H; ++h) { for (int w = 0; w < W; ++w) { if (table[h][w] != other.table[h][w]) return false; } } return true; } template bool operator!=(const matrix &other) { return !operator==(other); } /** * @brief サイズ n の単位行列。 */ static matrix E(int N) { matrix ret(N, N); for (int i = 0; i < N; i++) ret.table[i][i] = 1; return ret; } }; #line 8 "library/gandalfr/other/io_supporter.hpp" #line 1 "library/atcoder/modint.hpp" #line 6 "library/atcoder/modint.hpp" #include #ifdef _MSC_VER #include #endif #line 1 "library/atcoder/internal_math.hpp" #line 5 "library/atcoder/internal_math.hpp" #ifdef _MSC_VER #include #endif namespace atcoder { namespace internal { // @param m `1 <= m` // @return x mod m constexpr long long safe_mod(long long x, long long m) { x %= m; if (x < 0) x += m; return x; } // Fast modular multiplication by barrett reduction // Reference: https://en.wikipedia.org/wiki/Barrett_reduction // NOTE: reconsider after Ice Lake struct barrett { unsigned int _m; unsigned long long im; // @param m `1 <= m < 2^31` explicit barrett(unsigned int m) : _m(m), im((unsigned long long)(-1) / m + 1) {} // @return m unsigned int umod() const { return _m; } // @param a `0 <= a < m` // @param b `0 <= b < m` // @return `a * b % m` unsigned int mul(unsigned int a, unsigned int b) const { // [1] m = 1 // a = b = im = 0, so okay // [2] m >= 2 // im = ceil(2^64 / m) // -> im * m = 2^64 + r (0 <= r < m) // let z = a*b = c*m + d (0 <= c, d < m) // a*b * im = (c*m + d) * im = c*(im*m) + d*im = c*2^64 + c*r + d*im // c*r + d*im < m * m + m * im < m * m + 2^64 + m <= 2^64 + m * (m + 1) < 2^64 * 2 // ((ab * im) >> 64) == c or c + 1 unsigned long long z = a; z *= b; #ifdef _MSC_VER unsigned long long x; _umul128(z, im, &x); #else unsigned long long x = (unsigned long long)(((unsigned __int128)(z)*im) >> 64); #endif unsigned int v = (unsigned int)(z - x * _m); if (_m <= v) v += _m; return v; } }; // @param n `0 <= n` // @param m `1 <= m` // @return `(x ** n) % m` constexpr long long pow_mod_constexpr(long long x, long long n, int m) { if (m == 1) return 0; unsigned int _m = (unsigned int)(m); unsigned long long r = 1; unsigned long long y = safe_mod(x, m); while (n) { if (n & 1) r = (r * y) % _m; y = (y * y) % _m; n >>= 1; } return r; } // Reference: // M. Forisek and J. Jancina, // Fast Primality Testing for Integers That Fit into a Machine Word // @param n `0 <= n` constexpr bool is_prime_constexpr(int n) { if (n <= 1) return false; if (n == 2 || n == 7 || n == 61) return true; if (n % 2 == 0) return false; long long d = n - 1; while (d % 2 == 0) d /= 2; constexpr long long bases[3] = {2, 7, 61}; for (long long a : bases) { long long t = d; long long y = pow_mod_constexpr(a, t, n); while (t != n - 1 && y != 1 && y != n - 1) { y = y * y % n; t <<= 1; } if (y != n - 1 && t % 2 == 0) { return false; } } return true; } template constexpr bool is_prime = is_prime_constexpr(n); // @param b `1 <= b` // @return pair(g, x) s.t. g = gcd(a, b), xa = g (mod b), 0 <= x < b/g constexpr std::pair inv_gcd(long long a, long long b) { a = safe_mod(a, b); if (a == 0) return {b, 0}; // Contracts: // [1] s - m0 * a = 0 (mod b) // [2] t - m1 * a = 0 (mod b) // [3] s * |m1| + t * |m0| <= b long long s = b, t = a; long long m0 = 0, m1 = 1; while (t) { long long u = s / t; s -= t * u; m0 -= m1 * u; // |m1 * u| <= |m1| * s <= b // [3]: // (s - t * u) * |m1| + t * |m0 - m1 * u| // <= s * |m1| - t * u * |m1| + t * (|m0| + |m1| * u) // = s * |m1| + t * |m0| <= b auto tmp = s; s = t; t = tmp; tmp = m0; m0 = m1; m1 = tmp; } // by [3]: |m0| <= b/g // by g != b: |m0| < b/g if (m0 < 0) m0 += b / s; return {s, m0}; } // Compile time primitive root // @param m must be prime // @return primitive root (and minimum in now) constexpr int primitive_root_constexpr(int m) { if (m == 2) return 1; if (m == 167772161) return 3; if (m == 469762049) return 3; if (m == 754974721) return 11; if (m == 998244353) return 3; int divs[20] = {}; divs[0] = 2; int cnt = 1; int x = (m - 1) / 2; while (x % 2 == 0) x /= 2; for (int i = 3; (long long)(i)*i <= x; i += 2) { if (x % i == 0) { divs[cnt++] = i; while (x % i == 0) { x /= i; } } } if (x > 1) { divs[cnt++] = x; } for (int g = 2;; g++) { bool ok = true; for (int i = 0; i < cnt; i++) { if (pow_mod_constexpr(g, (m - 1) / divs[i], m) == 1) { ok = false; break; } } if (ok) return g; } } template constexpr int primitive_root = primitive_root_constexpr(m); // @param n `n < 2^32` // @param m `1 <= m < 2^32` // @return sum_{i=0}^{n-1} floor((ai + b) / m) (mod 2^64) unsigned long long floor_sum_unsigned(unsigned long long n, unsigned long long m, unsigned long long a, unsigned long long b) { unsigned long long ans = 0; while (true) { if (a >= m) { ans += n * (n - 1) / 2 * (a / m); a %= m; } if (b >= m) { ans += n * (b / m); b %= m; } unsigned long long y_max = a * n + b; if (y_max < m) break; // y_max < m * (n + 1) // floor(y_max / m) <= n n = (unsigned long long)(y_max / m); b = (unsigned long long)(y_max % m); std::swap(m, a); } return ans; } } // namespace internal } // namespace atcoder #line 1 "library/atcoder/internal_type_traits.hpp" #line 7 "library/atcoder/internal_type_traits.hpp" namespace atcoder { namespace internal { #ifndef _MSC_VER template using is_signed_int128 = typename std::conditional::value || std::is_same::value, std::true_type, std::false_type>::type; template using is_unsigned_int128 = typename std::conditional::value || std::is_same::value, std::true_type, std::false_type>::type; template using make_unsigned_int128 = typename std::conditional::value, __uint128_t, unsigned __int128>; template using is_integral = typename std::conditional::value || is_signed_int128::value || is_unsigned_int128::value, std::true_type, std::false_type>::type; template using is_signed_int = typename std::conditional<(is_integral::value && std::is_signed::value) || is_signed_int128::value, std::true_type, std::false_type>::type; template using is_unsigned_int = typename std::conditional<(is_integral::value && std::is_unsigned::value) || is_unsigned_int128::value, std::true_type, std::false_type>::type; template using to_unsigned = typename std::conditional< is_signed_int128::value, make_unsigned_int128, typename std::conditional::value, std::make_unsigned, std::common_type>::type>::type; #else template using is_integral = typename std::is_integral; template using is_signed_int = typename std::conditional::value && std::is_signed::value, std::true_type, std::false_type>::type; template using is_unsigned_int = typename std::conditional::value && std::is_unsigned::value, std::true_type, std::false_type>::type; template using to_unsigned = typename std::conditional::value, std::make_unsigned, std::common_type>::type; #endif template using is_signed_int_t = std::enable_if_t::value>; template using is_unsigned_int_t = std::enable_if_t::value>; template using to_unsigned_t = typename to_unsigned::type; } // namespace internal } // namespace atcoder #line 14 "library/atcoder/modint.hpp" namespace atcoder { namespace internal { struct modint_base {}; struct static_modint_base : modint_base {}; template using is_modint = std::is_base_of; template using is_modint_t = std::enable_if_t::value>; } // namespace internal template * = nullptr> struct static_modint : internal::static_modint_base { using mint = static_modint; public: static constexpr int mod() { return m; } static mint raw(int v) { mint x; x._v = v; return x; } static_modint() : _v(0) {} template * = nullptr> static_modint(T v) { long long x = (long long)(v % (long long)(umod())); if (x < 0) x += umod(); _v = (unsigned int)(x); } template * = nullptr> static_modint(T v) { _v = (unsigned int)(v % umod()); } unsigned int val() const { return _v; } mint& operator++() { _v++; if (_v == umod()) _v = 0; return *this; } mint& operator--() { if (_v == 0) _v = umod(); _v--; return *this; } mint operator++(int) { mint result = *this; ++*this; return result; } mint operator--(int) { mint result = *this; --*this; return result; } mint& operator+=(const mint& rhs) { _v += rhs._v; if (_v >= umod()) _v -= umod(); return *this; } mint& operator-=(const mint& rhs) { _v -= rhs._v; if (_v >= umod()) _v += umod(); return *this; } mint& operator*=(const mint& rhs) { unsigned long long z = _v; z *= rhs._v; _v = (unsigned int)(z % umod()); return *this; } mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); } mint operator+() const { return *this; } mint operator-() const { return mint() - *this; } mint pow(long long n) const { assert(0 <= n); mint x = *this, r = 1; while (n) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; } mint inv() const { if (prime) { assert(_v); return pow(umod() - 2); } else { auto eg = internal::inv_gcd(_v, m); assert(eg.first == 1); return eg.second; } } friend mint operator+(const mint& lhs, const mint& rhs) { return mint(lhs) += rhs; } friend mint operator-(const mint& lhs, const mint& rhs) { return mint(lhs) -= rhs; } friend mint operator*(const mint& lhs, const mint& rhs) { return mint(lhs) *= rhs; } friend mint operator/(const mint& lhs, const mint& rhs) { return mint(lhs) /= rhs; } friend bool operator==(const mint& lhs, const mint& rhs) { return lhs._v == rhs._v; } friend bool operator!=(const mint& lhs, const mint& rhs) { return lhs._v != rhs._v; } private: unsigned int _v; static constexpr unsigned int umod() { return m; } static constexpr bool prime = internal::is_prime; }; template struct dynamic_modint : internal::modint_base { using mint = dynamic_modint; public: static int mod() { return (int)(bt.umod()); } static void set_mod(int m) { assert(1 <= m); bt = internal::barrett(m); } static mint raw(int v) { mint x; x._v = v; return x; } dynamic_modint() : _v(0) {} template * = nullptr> dynamic_modint(T v) { long long x = (long long)(v % (long long)(mod())); if (x < 0) x += mod(); _v = (unsigned int)(x); } template * = nullptr> dynamic_modint(T v) { _v = (unsigned int)(v % mod()); } unsigned int val() const { return _v; } mint& operator++() { _v++; if (_v == umod()) _v = 0; return *this; } mint& operator--() { if (_v == 0) _v = umod(); _v--; return *this; } mint operator++(int) { mint result = *this; ++*this; return result; } mint operator--(int) { mint result = *this; --*this; return result; } mint& operator+=(const mint& rhs) { _v += rhs._v; if (_v >= umod()) _v -= umod(); return *this; } mint& operator-=(const mint& rhs) { _v += mod() - rhs._v; if (_v >= umod()) _v -= umod(); return *this; } mint& operator*=(const mint& rhs) { _v = bt.mul(_v, rhs._v); return *this; } mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); } mint operator+() const { return *this; } mint operator-() const { return mint() - *this; } mint pow(long long n) const { assert(0 <= n); mint x = *this, r = 1; while (n) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; } mint inv() const { auto eg = internal::inv_gcd(_v, mod()); assert(eg.first == 1); return eg.second; } friend mint operator+(const mint& lhs, const mint& rhs) { return mint(lhs) += rhs; } friend mint operator-(const mint& lhs, const mint& rhs) { return mint(lhs) -= rhs; } friend mint operator*(const mint& lhs, const mint& rhs) { return mint(lhs) *= rhs; } friend mint operator/(const mint& lhs, const mint& rhs) { return mint(lhs) /= rhs; } friend bool operator==(const mint& lhs, const mint& rhs) { return lhs._v == rhs._v; } friend bool operator!=(const mint& lhs, const mint& rhs) { return lhs._v != rhs._v; } private: unsigned int _v; static internal::barrett bt; static unsigned int umod() { return bt.umod(); } }; template internal::barrett dynamic_modint::bt(998244353); using modint998244353 = static_modint<998244353>; using modint1000000007 = static_modint<1000000007>; using modint = dynamic_modint<-1>; namespace internal { template using is_static_modint = std::is_base_of; template using is_static_modint_t = std::enable_if_t::value>; template struct is_dynamic_modint : public std::false_type {}; template struct is_dynamic_modint> : public std::true_type {}; template using is_dynamic_modint_t = std::enable_if_t::value>; } // namespace internal } // namespace atcoder #line 10 "library/gandalfr/other/io_supporter.hpp" template std::ostream &operator<<(std::ostream &os, const std::vector &v) { for (int i = 0; i < (int)v.size(); i++) os << v[i] << (i + 1 != (int)v.size() ? " " : ""); return os; } template std::ostream &operator<<(std::ostream &os, const std::set &st) { for (const T &x : st) { std::cout << x << " "; } return os; } template std::ostream &operator<<(std::ostream &os, const std::multiset &st) { for (const T &x : st) { std::cout << x << " "; } return os; } template std::ostream &operator<<(std::ostream &os, const std::deque &dq) { for (const T &x : dq) { std::cout << x << " "; } return os; } template std::ostream &operator<<(std::ostream &os, const std::pair &p) { os << p.first << ' ' << p.second; return os; } template std::ostream &operator<<(std::ostream &os, std::queue &q) { int sz = q.size(); while (--sz) { os << q.front() << ' '; q.push(q.front()); q.pop(); } os << q.front(); q.push(q.front()); q.pop(); return os; } namespace atcoder { template std::ostream &operator<<(std::ostream &os, const static_modint &mi) { os << mi.val(); return os; } template std::ostream &operator<<(std::ostream &os, const dynamic_modint &mi) { os << mi.val(); return os; } } template std::istream &operator>>(std::istream &is, std::vector &v) { for (T &in : v) is >> in; return is; } template std::istream &operator>>(std::istream &is, std::pair &p) { is >> p.first >> p.second; return is; } namespace atcoder { template std::istream &operator>>(std::istream &is, static_modint &mi) { long long n; is >> n; mi = n; return is; } template std::istream &operator>>(std::istream &is, dynamic_modint &mi) { long long n; is >> n; mi = n; return is; } } #line 4 "playspace/main.cpp" using namespace std; using ll = long long; const int INF = 1001001001; const ll INFLL = 1001001001001001001; const ll MOD = 1000000007; const ll _MOD = 998244353; #define rep(i, j, n) for(ll i = (ll)(j); i < (ll)(n); i++) #define rrep(i, j, n) for(ll i = (ll)(n-1); i >= (ll)(j); i--) #define all(a) (a).begin(),(a).end() #define debug(a) std::cerr << #a << ": " << a << std::endl #define LF cout << endl template inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); } template inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); } void Yes(bool ok){ std::cout << (ok ? "Yes" : "No") << std::endl; } int main(void){ int T; cin >> T; while (T--) { int N, M; cin >> N >> M; using mint = atcoder::modint998244353; matrix mt(3, 3); mt.row_assign(0, {1, N, (mint)N * (N - 3) / 2}); mt.row_assign(1, {1, N - 1, (mint)(N - 2) * (N - 3) / 2}); mt.row_assign(2, {1, N - 2, 1 + (mint)(N - 3) * (N - 4) / 2}); matrix base(1, 3), sum(3, 1, 1); base.row_assign(0, {1, N, (mint)N * (N - 3) / 2}); cout << (base * (mt ^ (M - 1)) * sum)(0, 0) << endl; } }