Submission #263033

#TimeUsernameProblemLanguageResultExecution timeMemory
263033KoDBoat (APIO16_boat)C++11
100 / 100
573 ms4480 KiB
/** * @title Template */ #include <iostream> #include <algorithm> #include <utility> #include <numeric> #include <vector> #include <array> #include <cassert> template <class T, class U> bool chmin(T &lhs, const U &rhs) { if (lhs > rhs) { lhs = rhs; return true; } return false; } template <class T, class U> bool chmax(T &lhs, const U &rhs) { if (lhs < rhs) { lhs = rhs; return true; } return false; } /** * @title Chmin/Chmax */ class range { public: class iterator { private: int64_t M_position; public: iterator(int64_t position) noexcept: M_position(position) { } void operator ++ () noexcept { ++M_position; } bool operator != (iterator other) const noexcept { return M_position != other.M_position; } int64_t operator * () const noexcept { return M_position; } }; class reverse_iterator { private: int64_t M_position; public: reverse_iterator(int64_t position) noexcept: M_position(position) { } void operator ++ () noexcept { --M_position; } bool operator != (reverse_iterator other) const noexcept { return M_position != other.M_position; } int64_t operator * () const noexcept { return M_position; } }; private: const iterator M_first, M_last; public: range(int64_t first, int64_t last) noexcept: M_first(first), M_last(std::max(first, last)) { } iterator begin() const noexcept { return M_first; } iterator end() const noexcept { return M_last; } reverse_iterator rbegin() const noexcept { return reverse_iterator(*M_last - 1); } reverse_iterator rend() const noexcept { return reverse_iterator(*M_first - 1); } }; /** * @title Range */ #include <type_traits> #include <iterator> template <class T> class rev_impl { public: using iterator = decltype(std::declval<T>().rbegin()); private: const iterator M_begin; const iterator M_end; public: rev_impl(T &&cont) noexcept: M_begin(cont.rbegin()), M_end(cont.rend()) { } iterator begin() const noexcept { return M_begin; } iterator end() const noexcept { return M_end; } }; template <class T> rev_impl<T> rev(T &&cont) { return rev_impl<T>(std::forward<T>(cont)); } /** * @title Reverser */ #include <cstdint> template <class Modulus> class modular { public: using value_type = uint32_t; using cover_type = uint64_t; static constexpr value_type mod() { return Modulus::value(); } template <class T> static value_type normalize(T value_) noexcept { if (value_ < 0) { value_ = -value_; value_ %= mod(); if (value_ == 0) return 0; return mod() - value_; } return value_ % mod(); } private: value_type value; public: modular() noexcept : value(0) { } template <class T> explicit modular(T value_) noexcept : value(normalize(value_)) { } template <class T> explicit operator T() const noexcept { return static_cast<T>(value); } value_type get() const noexcept { return value; } modular operator - () const noexcept { return modular(mod() - value); } modular operator ~ () const noexcept { return inverse(); } value_type &extract() noexcept { return value; } modular inverse() const noexcept { return power(mod() - 2); } modular power(cover_type exp) const noexcept { modular res(1), mult(*this); while (exp > 0) { if (exp & 1) res *= mult; mult *= mult; exp >>= 1; } return res; } modular operator + (const modular &rhs) const noexcept { return modular(*this) += rhs; } modular& operator += (const modular &rhs) noexcept { if ((value += rhs.value) >= mod()) value -= mod(); return *this; } modular operator - (const modular &rhs) const noexcept { return modular(*this) -= rhs; } modular& operator -= (const modular &rhs) noexcept { if ((value += mod() - rhs.value) >= mod()) value -= mod(); return *this; } modular operator * (const modular &rhs) const noexcept { return modular(*this) *= rhs; } modular& operator *= (const modular &rhs) noexcept { value = (cover_type) value * rhs.value % mod(); return *this; } modular operator / (const modular &rhs) const noexcept { return modular(*this) /= rhs; } modular& operator /= (const modular &rhs) noexcept { return (*this) *= rhs.inverse(); } bool zero() const noexcept { return value == 0; } bool operator == (const modular &rhs) const noexcept { return value == rhs.value; } 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 modular power(modular val, cover_type exp) noexcept { return val.power(exp); } friend modular inverse(modular val) noexcept { return val.inverse(); } }; template <uint32_t Val> struct modulus_impl { static constexpr uint32_t value() noexcept { return Val; } }; template <uint32_t Val> using mint32_t = modular<modulus_impl<Val>>; struct runtime_mod { static uint32_t &value() noexcept { static uint32_t val = 0; return val; } }; using rmint32_t = modular<runtime_mod>; /** * @title Modint */ #include <cstddef> template <class T, size_t N> class factorials { public: using value_type = T; static constexpr size_t size = N; public: std::array<value_type, size + 1> fact{}; std::array<value_type, size + 1> fact_inv{}; factorials() { fact.front() = value_type(1); for (size_t i = 1; i <= size; ++i) { fact[i] = fact[i - 1] * value_type(i); } fact_inv.back() = ~fact.back(); for (size_t i = size; i > 0; --i) { fact_inv[i - 1] = fact_inv[i] * value_type(i); } } value_type operator () (size_t n, size_t r) const { return fact[n] * fact_inv[n - r] * fact_inv[r]; } }; /** * @title Factorial */ 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>; factorials<m32, 500> fact; int main() { i32 N; std::cin >> N; std::vector<i32> L(N), R(N); std::vector<i32> comp; comp.reserve(2 * N); for (auto i: range(0, N)) { std::cin >> L[i] >> R[i]; ++R[i]; comp.push_back(L[i]); comp.push_back(R[i]); } std::sort(comp.begin(), comp.end()); comp.erase(std::unique(comp.begin(), comp.end()), comp.end()); for (auto i: range(0, N)) { L[i] = std::lower_bound(comp.cbegin(), comp.cend(), L[i]) - comp.cbegin(); R[i] = std::lower_bound(comp.cbegin(), comp.cend(), R[i]) - comp.cbegin(); } const i32 size = comp.size() - 1; std::vector<i32> len(size); std::vector<std::vector<m32>> dp(size); std::vector<std::vector<m32>> coeff(size); for (auto i: range(0, size)) { len[i] = comp[i + 1] - comp[i]; dp[i].resize(std::min(N, len[i]) + 1); coeff[i].resize(std::min(N, len[i]) + 1); m32 cur(1); for (auto j: range(1, std::min(N, len[i]) + 1)) { cur *= m32(len[i] - j + 1); coeff[i][j] = cur * fact.fact_inv[j]; } } for (auto i: range(0, N)) { m32 sum; for (auto j: range(0, L[i])) { for (auto k: range(1, std::min(N, len[j]) + 1)) { sum += dp[j][k] * coeff[j][k]; } } for (auto j: range(L[i], R[i])) { m32 add; for (auto k: range(1, std::min(N, len[j]) + 1)) { add += dp[j][k] * coeff[j][k]; } for (auto k: rev(range(1, std::min(N, len[j])))) { dp[j][k + 1] += dp[j][k]; } dp[j][1] += sum + m32(1); sum += add; } } m32 ans; for (auto j: range(0, size)) { for (auto k: range(1, std::min(N, len[j]) + 1)) { ans += dp[j][k] * coeff[j][k]; } } std::cout << ans << '\n'; return 0; }
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