#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=DPL_5_A&lang=ja" #include <iostream> #include <type_traits> #include "../../Math/Modulo/mod-int.hpp" #include "../../Algorithm/doubling-pow.hpp" #include "../../Util/IO/println.hpp" int main() { using Mint = ModInt1000000007; int n; std::cin >> n; Mint k; std::cin >> k; const auto ans1 = k.pow(n); const auto ans2 = doublingPow(k, n); static_assert(std::is_same_v<decltype(ans1), decltype(ans2)>); assert(ans1 == ans2); println(ans1); return 0; }
#line 1 "test/AOJ/DPL_5_A.test.cpp" #define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=DPL_5_A&lang=ja" #include <iostream> #include <type_traits> #line 2 "Math/Modulo/mod-int.hpp" #include <cstdint> #include <cassert> #line 5 "Math/Modulo/mod-int.hpp" #include <limits> /** * @brief Mod-Int (コンパイル時mod型と実行時mod型) */ namespace internal { template <class ModHolder> class ModInt { private: int64_t value; public: constexpr ModInt() noexcept : value(0) {} constexpr ModInt(int64_t v) noexcept : value(ModInt::normalized(v)) {} static constexpr const ModInt raw(int64_t v) noexcept { ModInt ret; ret.value = v; return ret; } static constexpr ModInt nullopt() noexcept { return ModInt::raw(std::numeric_limits<int64_t>::min()); } constexpr bool isNull() const noexcept { return *this == ModInt::nullopt(); } static constexpr int64_t mod() { return ModHolder::mod; } static int64_t setMod(int64_t m) noexcept { assert(m >= 1); return ModHolder::mod = m; } template <class T> constexpr explicit operator T() const noexcept { return static_cast<T>(value); } constexpr int64_t val() const noexcept { return value; } constexpr ModInt& operator+=(const ModInt& rhs) noexcept { if ((value += rhs.value) >= mod()) value -= mod(); return *this; } constexpr ModInt& operator-=(const ModInt& rhs) noexcept { if ((value -= rhs.value) < 0) value += mod(); return *this; } constexpr ModInt& operator*=(const ModInt& rhs) noexcept { (value *= rhs.value) %= mod(); return *this; } constexpr ModInt& operator/=(const ModInt& rhs) noexcept { return *this *= rhs.inv(); } constexpr const ModInt inv() const noexcept { return ModInt(ModInt::inverse(value, mod())); } constexpr const ModInt operator+() const noexcept { return *this; } constexpr const ModInt operator-() const noexcept { return ModInt(-value); } constexpr const ModInt pow(int64_t expv) const noexcept { int64_t ret = 1, square = value; for (uint64_t p = std::abs(expv); p; p >>= 1) { if (p & 1) (ret *= square) %= mod(); (square *= square) %= mod(); } return (expv < 0) ? (ModInt::raw(1) / ModInt::raw(ret)) : ModInt::raw(ret); } friend constexpr bool operator==(const ModInt& lhs, const ModInt& rhs) noexcept { return lhs.value == rhs.value; } friend constexpr bool operator!=(const ModInt& lhs, const ModInt& rhs) noexcept { return lhs.value != rhs.value; } friend constexpr const ModInt operator+(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) += rhs; } friend constexpr const ModInt operator-(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) -= rhs; } friend constexpr const ModInt operator*(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) *= rhs; } friend constexpr const ModInt operator/(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) /= rhs; } friend std::ostream& operator<<(std::ostream& os, const ModInt& x) { #ifdef LOCAL_DEBUG if (x.isNull()) return os << "{nullopt}"; #endif return os << x.value; } friend std::istream& operator>>(std::istream& is, ModInt& x) { is >> x.value; x.value = ModInt::normalized(x.value); return is; } private: static constexpr int64_t normalized(int64_t n) { n = (-mod() <= n && n < mod() ? n : n % mod()); if (n < 0) n += mod(); return n; } static constexpr int64_t inverse(int64_t a, int64_t m) { int64_t u = 0, v = 1; while (a != 0) { const auto t = m / a; static_cast<void>(m -= t * a), std::swap(m, a); static_cast<void>(u -= t * v), std::swap(u, v); } assert(m == 1); return u; } }; template <int64_t Mod> struct StaticModHolder { static constexpr int64_t mod = Mod; }; template <int ID> struct DynamicModHolder { static int64_t mod; }; template <int ID> int64_t DynamicModHolder<ID>::mod; } // namespace internal template <int64_t Mod> using StaticModInt = internal::ModInt<internal::StaticModHolder<Mod>>; using ModInt1000000007 = StaticModInt<int(1e9) + 7>; using ModInt998244353 = StaticModInt<998244353>; template <int ID> using DynamicModInt = internal::ModInt<internal::DynamicModHolder<ID>>; #line 2 "Algorithm/doubling-pow.hpp" #include <cmath> #line 3 "Util/int-alias.hpp" /** * @brief int-alias (整数型のエイリアス) */ using i64 = int64_t; using u64 = uint64_t; #line 4 "Algorithm/doubling-pow.hpp" /** * @brief doubling-pow() (繰り返し二乗法) */ template <class Integer> constexpr Integer doublingPow(const Integer& n, const i64 expv) { Integer ret = 1, square = n; for (u64 p = std::abs(expv); p; p >>= 1) { if (p & 1) ret *= square; square *= square; } return (expv < 0) ? (1 / ret) : ret; } #line 3 "Util/IO/println.hpp" #include <utility> /** * @brief println() (可変個の値を空白区切りで出力して改行する) */ inline void println() { std::cout << '\n'; } template <class Head, class... Tail> inline void println(Head&& head, Tail&&... tail) { std::cout << head << &" "[!sizeof...(tail)]; println(std::forward<Tail>(tail)...); } #line 9 "test/AOJ/DPL_5_A.test.cpp" int main() { using Mint = ModInt1000000007; int n; std::cin >> n; Mint k; std::cin >> k; const auto ans1 = k.pow(n); const auto ans2 = doublingPow(k, n); static_assert(std::is_same_v<decltype(ans1), decltype(ans2)>); assert(ans1 == ans2); println(ans1); return 0; }