#line 1 "main.cpp" /** * @title Template */ #include #include #include #include #include #include #include #line 2 "/Users/kodamankod/Desktop/cpp_programming/Library/other/chmin_chmax.cpp" template constexpr bool chmin(T &lhs, const U &rhs) { if (lhs > rhs) { lhs = rhs; return true; } return false; } template constexpr bool chmax(T &lhs, const U &rhs) { if (lhs < rhs) { lhs = rhs; return true; } return false; } /** * @title Chmin/Chmax */ #line 2 "/Users/kodamankod/Desktop/cpp_programming/Library/other/range.cpp" #line 4 "/Users/kodamankod/Desktop/cpp_programming/Library/other/range.cpp" class range { public: class iterator { private: int64_t M_position; public: constexpr iterator(int64_t position) noexcept: M_position(position) { } constexpr void operator ++ () noexcept { ++M_position; } constexpr bool operator != (iterator other) const noexcept { return M_position != other.M_position; } constexpr int64_t operator * () const noexcept { return M_position; } }; class reverse_iterator { private: int64_t M_position; public: constexpr reverse_iterator(int64_t position) noexcept: M_position(position) { } constexpr void operator ++ () noexcept { --M_position; } constexpr bool operator != (reverse_iterator other) const noexcept { return M_position != other.M_position; } constexpr int64_t operator * () const noexcept { return M_position; } }; private: const iterator M_first, M_last; public: constexpr range(int64_t first, int64_t last) noexcept: M_first(first), M_last(std::max(first, last)) { } constexpr iterator begin() const noexcept { return M_first; } constexpr iterator end() const noexcept { return M_last; } constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator(*M_last - 1); } constexpr reverse_iterator rend() const noexcept { return reverse_iterator(*M_first - 1); } }; /** * @title Range */ #line 2 "/Users/kodamankod/Desktop/cpp_programming/Library/other/rev.cpp" #include #include #line 6 "/Users/kodamankod/Desktop/cpp_programming/Library/other/rev.cpp" template class rev_impl { public: using iterator = decltype(std::rbegin(std::declval())); private: const iterator M_begin; const iterator M_end; public: constexpr rev_impl(T &&cont) noexcept: M_begin(std::rbegin(cont)), M_end(std::rend(cont)) { } constexpr iterator begin() const noexcept { return M_begin; } constexpr iterator end() const noexcept { return M_end; } }; template constexpr decltype(auto) rev(T &&cont) { return rev_impl(std::forward(cont)); } /** * @title Reverser */ #line 2 "/Users/kodamankod/Desktop/cpp_programming/Library/algebraic/modular.cpp" #line 2 "/Users/kodamankod/Desktop/cpp_programming/Library/algebraic/mod_inv.cpp" #line 4 "/Users/kodamankod/Desktop/cpp_programming/Library/algebraic/mod_inv.cpp" #include constexpr std::pair mod_inv(int64_t a, int64_t b) { if ((a %= b) == 0) return { b, 0 }; int64_t s = b, t = (a < 0 ? a + b : a); int64_t m0 = 0, m1 = 1, tmp = 0; while (t > 0) { const auto u = s / t; s -= t * u; m0 -= m1 * u; tmp = s; s = t; t = tmp; tmp = m0; m0 = m1; m1 = tmp; } return { s, (m0 < 0 ? m0 + b / s : m0) }; } /** * @title Extended GCD */ #line 4 "/Users/kodamankod/Desktop/cpp_programming/Library/algebraic/modular.cpp" #line 8 "/Users/kodamankod/Desktop/cpp_programming/Library/algebraic/modular.cpp" #include template class modular { public: using value_type = uint32_t; using cover_type = uint64_t; template static constexpr value_type normalize(T value_) noexcept { if (value_ < 0) { value_ = -value_; value_ %= Modulus::mod(); if (value_ == 0) return 0; return Modulus::mod() - value_; } return value_ % Modulus::mod(); } private: value_type value; template * = nullptr> constexpr modular inverse_helper() const noexcept { return power(*this, Modulus::mod() - 2); } template * = nullptr> constexpr modular inverse_helper() const noexcept { const auto tmp = mod_inv(value, Modulus::mod()); assert(tmp.first == 1); return modular(tmp.second); } public: constexpr modular() noexcept : value(0) { } template explicit constexpr modular(T value_) noexcept : value(normalize(value_)) { } template explicit constexpr operator T() const noexcept { return static_cast(value); } constexpr value_type get() const noexcept { return value; } constexpr value_type &extract() noexcept { return value; } constexpr modular operator - () const noexcept { return modular(Modulus::mod() - value); } constexpr modular operator ~ () const noexcept { return inverse(*this); } constexpr modular operator + (const modular &rhs) const noexcept { return modular(*this) += rhs; } constexpr modular& operator += (const modular &rhs) noexcept { if ((value += rhs.value) >= Modulus::mod()) value -= Modulus::mod(); return *this; } constexpr modular operator - (const modular &rhs) const noexcept { return modular(*this) -= rhs; } constexpr modular& operator -= (const modular &rhs) noexcept { if ((value += Modulus::mod() - rhs.value) >= Modulus::mod()) value -= Modulus::mod(); return *this; } constexpr modular operator * (const modular &rhs) const noexcept { return modular(*this) *= rhs; } constexpr modular& operator *= (const modular &rhs) noexcept { value = (cover_type) value * rhs.value % Modulus::mod(); return *this; } constexpr modular operator / (const modular &rhs) const noexcept { return modular(*this) /= rhs; } constexpr modular& operator /= (const modular &rhs) noexcept { return (*this) *= inverse(rhs); } constexpr bool zero() const noexcept { return value == 0; } constexpr bool operator == (const modular &rhs) const noexcept { return value == rhs.value; } constexpr bool operator != (const modular &rhs) const noexcept { return value != rhs.value; } friend std::ostream& operator << (std::ostream &stream, const modular &rhs) { return stream << rhs.value; } friend constexpr modular inverse(const modular &val) noexcept { return val.inverse_helper(); } friend constexpr modular power(modular val, cover_type exp) noexcept { modular res(1); for (; exp > 0; exp >>= 1, val *= val) if (exp & 1) res *= val; return res; } }; template struct static_modulus { static constexpr uint32_t mod() noexcept { return Mod; } static constexpr bool is_prime = IsPrime; }; template struct dynamic_modulus { static uint32_t &mod() noexcept { static uint32_t val = 0; return val; } static constexpr bool is_prime = IsPrime; }; template using mint32_t = modular>; using rmint32_t = modular>; /* * @title Modint */ #line 18 "main.cpp" using i32 = int32_t; using i64 = int64_t; using u32 = uint32_t; using u64 = uint64_t; constexpr i32 inf32 = (i32(1) << 30) - 1; constexpr i64 inf64 = (i64(1) << 62) - 1; using m32 = mint32_t<1000000007>; constexpr size_t adjust = 10250; int main() { i32 N, K; std::cin >> N >> K; std::vector A(N); for (auto &x: A) { std::cin >> x; x -= K; } std::array dp{}; dp[adjust] = m32(1); for (const auto x: A) { std::array next{}; for (auto i: range(0, 20500)) { if (i + x >= 0 && i + x < 20500) { next[i + x] += dp[i]; } next[i] += dp[i]; } dp = std::move(next); } m32 ans; for (auto i: range(adjust, 20500)) { ans += dp[i]; } std::cout << ans - m32(1) << '\n'; return 0; }