#include using namespace std; using lint = long long int; using pint = pair; using plint = pair; struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_; #define ALL(x) (x).begin(), (x).end() #define SZ(x) ((lint)(x).size()) #define POW2(n) (1LL << (n)) #define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i=i##_begin_;i--) #define REP(i, n) FOR(i,0,n) #define IREP(i, n) IFOR(i,0,n) template void ndarray(vector &vec, int len) { vec.resize(len); } template void ndarray(vector &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); } template bool mmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; } template bool mmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; } template pair operator+(const pair &l, const pair &r) { return make_pair(l.first + r.first, l.second + r.second); } template pair operator-(const pair &l, const pair &r) { return make_pair(l.first - r.first, l.second - r.second); } template istream &operator>>(istream &is, vector &vec){ for (auto &v : vec) is >> v; return is; } ///// This part below is only for debug, not used ///// template ostream &operator<<(ostream &os, const vector &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; } template ostream &operator<<(ostream &os, const deque &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; } template ostream &operator<<(ostream &os, const set &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_set &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const multiset &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_multiset &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const pair &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; } template ostream &operator<<(ostream &os, const map &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_map &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; } #define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl; ///// END ///// /* #include #include #include using namespace __gnu_pbds; // find_by_order(), order_of_key() template using pbds_set = tree, rb_tree_tag, tree_order_statistics_node_update>; template using pbds_map = tree, rb_tree_tag, tree_order_statistics_node_update>; */ #line 2 "modulus/modint_fixed.hpp" #include #include #include template struct ModInt { using lint = long long; static int get_mod() { return mod; } static int get_primitive_root() { static int primitive_root = 0; if (!primitive_root) { primitive_root = [&](){ std::set fac; int v = mod - 1; for (lint i = 2; i * i <= v; i++) while (v % i == 0) fac.insert(i), v /= i; if (v > 1) fac.insert(v); for (int g = 1; g < mod; g++) { bool ok = true; for (auto i : fac) if (ModInt(g).power((mod - 1) / i) == 1) { ok = false; break; } if (ok) return g; } return -1; }(); } return primitive_root; } int val; constexpr ModInt() : val(0) {} constexpr ModInt &_setval(lint v) { val = (v >= mod ? v - mod : v); return *this; } constexpr ModInt(lint v) { _setval(v % mod + mod); } explicit operator bool() const { return val != 0; } constexpr ModInt operator+(const ModInt &x) const { return ModInt()._setval((lint)val + x.val); } constexpr ModInt operator-(const ModInt &x) const { return ModInt()._setval((lint)val - x.val + mod); } constexpr ModInt operator*(const ModInt &x) const { return ModInt()._setval((lint)val * x.val % mod); } constexpr ModInt operator/(const ModInt &x) const { return ModInt()._setval((lint)val * x.inv() % mod); } constexpr ModInt operator-() const { return ModInt()._setval(mod - val); } constexpr ModInt &operator+=(const ModInt &x) { return *this = *this + x; } constexpr ModInt &operator-=(const ModInt &x) { return *this = *this - x; } constexpr ModInt &operator*=(const ModInt &x) { return *this = *this * x; } constexpr ModInt &operator/=(const ModInt &x) { return *this = *this / x; } friend constexpr ModInt operator+(lint a, const ModInt &x) { return ModInt()._setval(a % mod + x.val); } friend constexpr ModInt operator-(lint a, const ModInt &x) { return ModInt()._setval(a % mod - x.val + mod); } friend constexpr ModInt operator*(lint a, const ModInt &x) { return ModInt()._setval(a % mod * x.val % mod); } friend constexpr ModInt operator/(lint a, const ModInt &x) { return ModInt()._setval(a % mod * x.inv() % mod); } constexpr bool operator==(const ModInt &x) const { return val == x.val; } constexpr bool operator!=(const ModInt &x) const { return val != x.val; } bool operator<(const ModInt &x) const { return val < x.val; } // To use std::map friend std::istream &operator>>(std::istream &is, ModInt &x) { lint t; is >> t; x = ModInt(t); return is; } friend std::ostream &operator<<(std::ostream &os, const ModInt &x) { os << x.val; return os; } constexpr lint power(lint n) const { lint ans = 1, tmp = this->val; while (n) { if (n & 1) ans = ans * tmp % mod; tmp = tmp * tmp % mod; n /= 2; } return ans; } constexpr lint inv() const { return this->power(mod - 2); } constexpr ModInt operator^(lint n) const { return ModInt(this->power(n)); } constexpr ModInt &operator^=(lint n) { return *this = *this ^ n; } inline ModInt fac() const { static std::vector facs; int l0 = facs.size(); if (l0 > this->val) return facs[this->val]; facs.resize(this->val + 1); for (int i = l0; i <= this->val; i++) facs[i] = (i == 0 ? ModInt(1) : facs[i - 1] * ModInt(i)); return facs[this->val]; } ModInt doublefac() const { lint k = (this->val + 1) / 2; if (this->val & 1) return ModInt(k * 2).fac() / ModInt(2).power(k) / ModInt(k).fac(); else return ModInt(k).fac() * ModInt(2).power(k); } ModInt nCr(const ModInt &r) const { if (this->val < r.val) return ModInt(0); return this->fac() / ((*this - r).fac() * r.fac()); } ModInt sqrt() const { if (val == 0) return 0; if (mod == 2) return val; if (power((mod - 1) / 2) != 1) return 0; ModInt b = 1; while (b.power((mod - 1) / 2) == 1) b += 1; int e = 0, m = mod - 1; while (m % 2 == 0) m >>= 1, e++; ModInt x = power((m - 1) / 2), y = (*this) * x * x; x *= (*this); ModInt z = b.power(m); while (y != 1) { int j = 0; ModInt t = y; while (t != 1) j++, t *= t; z = z.power(1LL << (e - j - 1)); x *= z, z *= z, y *= z; e = j; } return ModInt(std::min(x.val, mod - x.val)); } }; using mint = ModInt<1000000007>; #line 3 "convolution/ntt.hpp" #include #include #include #include using namespace std; // Integer convolution for arbitrary mod // with NTT (and Garner's algorithm) for ModInt / ModIntRuntime class. // We skip Garner's algorithm if `skip_garner` is true or mod is in `nttprimes`. // input: a (size: n), b (size: m) // return: vector (size: n + m - 1) template vector nttconv(vector a, vector b, bool skip_garner = false); constexpr int nttprimes[3] = {998244353, 167772161, 469762049}; // Integer FFT (Fast Fourier Transform) for ModInt class // (Also known as Number Theoretic Transform, NTT) // is_inverse: inverse transform // ** Input size must be 2^n ** template void ntt(vector &a, bool is_inverse = false) { int n = a.size(); assert(__builtin_popcount(n) == 1); MODINT h = MODINT(MODINT::get_primitive_root()).power((MODINT::get_mod() - 1) / n); if (is_inverse) h = 1 / h; int i = 0; for (int j = 1; j < n - 1; j++) { for (int k = n >> 1; k > (i ^= k); k >>= 1); if (j < i) swap(a[i], a[j]); } for (int m = 1; m < n; m *= 2) { int m2 = 2 * m; long long int base = h.power(n / m2); MODINT w(1); for(int x = 0; x < m; x++) { for (int s = x; s < n; s += m2) { MODINT u = a[s], d = a[s + m] * w; a[s] = u + d, a[s + m] = u - d; } w *= base; } } if (is_inverse) { long long int n_inv = MODINT(n).inv(); for (auto &v : a) v *= n_inv; } } template vector> nttconv_(const vector &a, const vector &b) { int sz = a.size(); assert(a.size() == b.size() and __builtin_popcount(sz) == 1); vector> ap(sz), bp(sz); for (int i = 0; i < sz; i++) ap[i] = a[i], bp[i] = b[i]; if (a == b) { ntt(ap, false); bp = ap; } else { ntt(ap, false); ntt(bp, false); } for (int i = 0; i < sz; i++) ap[i] *= bp[i]; ntt(ap, true); return ap; } long long int extgcd_ntt_(long long int a, long long int b, long long int &x, long long int &y) { long long int d = a; if (b != 0) d = extgcd_ntt_(b, a % b, y, x), y -= (a / b) * x; else x = 1, y = 0; return d; } long long int modinv_ntt_(long long int a, long long int m) { long long int x, y; extgcd_ntt_(a, m, x, y); return (m + x % m) % m; } long long int garner_ntt_(int r0, int r1, int r2, int mod) { array rs = {r0, r1, r2, 0}; vector coffs(4, 1), constants(4, 0); for (int i = 0; i < 3; i++) { long long int v = (rs[i] - constants[i]) * modinv_ntt_(coffs[i], nttprimes[i]) % nttprimes[i]; if (v < 0) v += nttprimes[i]; for (int j = i + 1; j < 4; j++) { (constants[j] += coffs[j] * v) %= (j < 3 ? nttprimes[j] : mod); (coffs[j] *= nttprimes[i]) %= (j < 3 ? nttprimes[j] : mod); } } return constants.back(); } template vector nttconv(vector a, vector b, bool skip_garner) { int sz = 1, n = a.size(), m = b.size(); while (sz < n + m) sz <<= 1; int mod = MODINT::get_mod(); if (skip_garner or find(begin(nttprimes), end(nttprimes), mod) != end(nttprimes)) { a.resize(sz), b.resize(sz); if (a == b) { ntt(a, false); b = a; } else ntt(a, false), ntt(b, false); for (int i = 0; i < sz; i++) a[i] *= b[i]; ntt(a, true); a.resize(n + m - 1); } else { vector ai(sz), bi(sz); for (int i = 0; i < n; i++) ai[i] = a[i].val; for (int i = 0; i < m; i++) bi[i] = b[i].val; auto ntt0 = nttconv_(ai, bi); auto ntt1 = nttconv_(ai, bi); auto ntt2 = nttconv_(ai, bi); a.resize(n + m - 1); for (int i = 0; i < n + m - 1; i++) { a[i] = garner_ntt_(ntt0[i].val, ntt1[i].val, ntt2[i].val, mod); } } return a; } #line 3 "formal_power_series/formal_power_series.hpp" #include #include #include using namespace std; // Formal Power Series (形式的冪級数) based on ModInt / ModIntRuntime // Reference: template struct FormalPowerSeries : vector { using vector::vector; using P = FormalPowerSeries; void shrink() { while (this->size() and this->back() == T(0)) this->pop_back(); } P operator+(const P &r) const { return P(*this) += r; } P operator+(const T &v) const { return P(*this) += v; } P operator-(const P &r) const { return P(*this) -= r; } P operator-(const T &v) const { return P(*this) -= v; } P operator*(const P &r) const { return P(*this) *= r; } P operator*(const T &v) const { return P(*this) *= v; } P operator/(const P &r) const { return P(*this) /= r; } P operator/(const T &v) const { return P(*this) /= v; } P operator%(const P &r) const { return P(*this) %= r; } P &operator+=(const P &r) { if (r.size() > this->size()) this->resize(r.size()); for (int i = 0; i < (int)r.size(); i++) (*this)[i] += r[i]; shrink(); return *this; } P &operator+=(const T &v) { if (this->empty()) this->resize(1); (*this)[0] += v; shrink(); return *this; } P &operator-=(const P &r) { if (r.size() > this->size()) this->resize(r.size()); for (int i = 0; i < (int)r.size(); i++) (*this)[i] -= r[i]; shrink(); return *this; } P &operator-=(const T &v) { if (this->empty()) this->resize(1); (*this)[0] -= v; shrink(); return *this; } P &operator*=(const T &v) { for (auto &x : (*this)) x *= v; shrink(); return *this; } P &operator*=(const P &r) { if (this->empty() || r.empty()) this->clear(); else { auto ret = nttconv(*this, r); *this = P(ret.begin(), ret.end()); } return *this; } P &operator%=(const P &r) { *this -= *this / r * r; shrink(); return *this; } P operator-() const { P ret = *this; for (auto &v : ret) v = -v; return ret; } P &operator/=(const T &v) { assert(v != T(0)); for (auto &x : (*this)) x /= v; return *this; } P &operator/=(const P &r) { if (this->size() < r.size()) { this->clear(); return *this; } int n = (int)this->size() - r.size() + 1; return *this = (reversed().pre(n) * r.reversed().inv(n)).pre(n).reversed(n); } P pre(int sz) const { P ret(this->begin(), this->begin() + min((int)this->size(), sz)); ret.shrink(); return ret; } P operator>>(int sz) const { if ((int)this->size() <= sz) return {}; return P(this->begin() + sz, this->end()); } P operator<<(int sz) const { if (this->empty()) return {}; P ret(*this); ret.insert(ret.begin(), sz, T(0)); return ret; } P reversed(int deg = -1) const { assert(deg >= -1); P ret(*this); if (deg != -1) ret.resize(deg, T(0)); reverse(ret.begin(), ret.end()); ret.shrink(); return ret; } P differential() const { // formal derivative (differential) of f.p.s. const int n = (int)this->size(); P ret(max(0, n - 1)); for (int i = 1; i < n; i++) ret[i - 1] = (*this)[i] * T(i); return ret; } P integral() const { const int n = (int)this->size(); P ret(n + 1); ret[0] = T(0); for (int i = 0; i < n; i++) ret[i + 1] = (*this)[i] / T(i + 1); return ret; } P inv(int deg) const { assert(deg >= -1); assert(this->size() and ((*this)[0]) != T(0)); // Requirement: F(0) != 0 const int n = this->size(); if (deg == -1) deg = n; P ret({T(1) / (*this)[0]}); for (int i = 1; i < deg; i <<= 1) { ret = (ret + ret - ret * ret * pre(i << 1)).pre(i << 1); } ret = ret.pre(deg); ret.shrink(); return ret; } P log(int deg = -1) const { assert(deg >= -1); assert(this->size() and ((*this)[0]) == T(1)); // Requirement: F(0) = 1 const int n = (int)this->size(); if (deg == 0) return {}; if (deg == -1) deg = n; return (this->differential() * this->inv(deg)).pre(deg - 1).integral(); } P sqrt(int deg = -1) const { assert(deg >= -1); const int n = (int)this->size(); if (deg == -1) deg = n; if (this->empty()) return {}; if ((*this)[0] == T(0)) { for (int i = 1; i < n; i++) if ((*this)[i] != T(0)) { if ((i & 1) or deg - i / 2 <= 0) return {}; return (*this >> i).sqrt(deg - i / 2) << (i / 2); } return {}; } T sqrtf0 = (*this)[0].sqrt(); if (sqrtf0 == T(0)) return {}; P y = (*this) / (*this)[0], ret({T(1)}); T inv2 = T(1) / T(2); for (int i = 1; i < deg; i <<= 1) { ret = (ret + y.pre(i << 1) * ret.inv(i << 1)) * inv2; } return ret.pre(deg) * sqrtf0; } P exp(int deg = -1) const { assert(deg >= -1); assert(this->empty() or ((*this)[0]) == T(0)); // Requirement: F(0) = 0 const int n = (int)this->size(); if (deg == -1) deg = n; P ret({T(1)}); for (int i = 1; i < deg; i <<= 1) { ret = (ret * (pre(i << 1) + T(1) - ret.log(i << 1))).pre(i << 1); } return ret.pre(deg); } P pow(long long int k, int deg = -1) const { assert(deg >= -1); const int n = (int)this->size(); if (deg == -1) deg = n; for (int i = 0; i < n; i++) { if ((*this)[i] != T(0)) { T rev = T(1) / (*this)[i]; P C(*this * rev); P D(n - i); for (int j = i; j < n; j++) D[j - i] = C[j]; D = (D.log(deg) * T(k)).exp(deg) * (*this)[i].power(k); P E(deg); if (k * (i > 0) > deg or k * i > deg) return {}; long long int S = i * k; for (int j = 0; j + S < deg and j < (int)D.size(); j++) E[j + S] = D[j]; E.shrink(); return E; } } return *this; } T coeff(int i) const { if ((int)this->size() <= i) return T(0); return (*this)[i]; } T eval(T x) const { T ret = 0, w = 1; for (auto &v : *this) ret += w * v, w *= x; return ret; } }; #pragma once #include #include #include #include template struct matrix { int H, W; std::vector elem; typename std::vector::iterator operator[](int i) { return elem.begin() + i * W; } inline T &at(int i, int j) { return elem[i * W + j]; } inline T get(int i, int j) const { return elem[i * W + j]; } operator std::vector>() const { std::vector> ret(H); for (int i = 0; i < H; i++) std::copy(elem.begin() + i * W, elem.begin() + (i + 1) * W, std::back_inserter(ret[i])); return ret; } matrix(int H = 0, int W = 0) : H(H), W(W), elem(H * W) {} matrix(const std::vector> &d) : H(d.size()), W(d.size() ? d[0].size() : 0) { for (auto &raw : d) std::copy(raw.begin(), raw.end(), std::back_inserter(elem)); } static matrix Identity(int N) { matrix ret(N, N); for (int i = 0; i < N; i++) ret.at(i, i) = 1; return ret; } matrix operator-() const { matrix ret(H, W); for (int i = 0; i < H * W; i++) ret.elem[i] = -elem[i]; return ret; } matrix operator+(const matrix &r) const { matrix ret(H, W); for (int i = 0; i < H * W; i++) ret.elem[i] += r.elem[i]; return ret; } matrix operator-(const matrix &r) const { matrix ret(H, W); for (int i = 0; i < H * W; i++) ret.elem[i] -= r.elem[i]; return ret; } matrix operator*(const matrix &r) const { matrix ret(H, r.W); for (int i = 0; i < H; i++) { for (int k = 0; k < W; k++) { for (int j = 0; j < r.W; j++) { ret.at(i, j) += this->get(i, k) * r.get(k, j); } } } return ret; } matrix &operator+=(const matrix &r) { return *this = *this + r; } matrix &operator-=(const matrix &r) { return *this = *this - r; } matrix &operator*=(const matrix &r) { return *this = *this * r; } bool operator==(const matrix &r) const { return H == r.H and W == r.W and elem == r.elem; } bool operator!=(const matrix &r) const { return H != r.H or W != r.W or elem != r.elem; } bool operator<(const matrix &r) const { return elem < r.elem; } matrix pow(int64_t n) const { matrix ret = Identity(H); if (n == 0) return ret; for (int i = 63 - __builtin_clzll(n); i >= 0; i--) { ret *= ret; if ((n >> i) & 1) ret *= (*this); } return ret; } matrix transpose() const { matrix ret(W, H); for (int i = 0; i < H; i++) for (int j = 0; j < W; j++) ret.at(j, i) = this->get(i, j); return ret; } // Gauss-Jordan elimination // - Require inverse for every non-zero element // - Complexity: O(H^2 W) matrix gauss_jordan() const { int c = 0; matrix mtr(*this); for (int h = 0; h < H; h++) { if (c == W) break; int piv = -1; for (int j = h; j < H; j++) if (mtr.get(j, c)) { piv = j; break; } if (piv == -1) { c++; h--; continue; } if (h != piv) { for (int w = 0; w < W; w++) { std::swap(mtr[piv][w], mtr[h][w]); mtr.at(piv, w) *= -1; // To preserve sign of determinant } } for (int hh = 0; hh < H; hh++) if (hh != h) { T coeff = mtr.at(hh, c) * mtr.at(h, c).inv(); for (int w = W - 1; w >= c; w--) { mtr.at(hh, w) -= mtr.at(h, w) * coeff; } } c++; } return mtr; } int rank_of_gauss_jordan() const { for (int i = H * W - 1; i >= 0; i--) if (elem[i]) return i / W + 1; return 0; } T determinant_of_upper_triangle() const { T ret = 1; for (int i = 0; i < H; i++) ret *= get(i, i); return ret; } friend std::ostream &operator<<(std::ostream &os, const matrix &x) { os << "[(" << x.H << " * " << x.W << " matrix)"; for (int i = 0; i < x.H; i++) { os << "\n["; for (int j = 0; j < x.W; j++) os << x.get(i, j) << ","; os << "]"; } os << "]\n"; return os; } friend std::istream &operator>>(std::istream &is, matrix &x) { for (auto &v : x.elem) is >> v; return is; } }; int main() { lint N, W, K; cin >> N >> W >> K; vector A(N); cin >> A; FormalPowerSeries fps(82); for (auto a : A) fps[a] += 1; dbg(fps); fps = fps * (-fps + 1).inv(82); matrix trans(2, 2); trans[0][1] = 1; trans[1][0] = fps.at(W * 2) - fps.at(W) * fps.at(W); trans[1][1] = fps.at(W); dbg(trans); trans = trans.pow(K); dbg(trans); cout << trans[1][1] << endl; }