Library/Algebraic/SemiGroup.hpp

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• Last update: 2024-12-27 16:29:20+09:00
• Include: #include "Library/Algebraic/SemiGroup.hpp"

Required by

• Library/DataStructure/DisjointSparseTable.hpp

Verified with

• Test/DataStructure/DisjointSparseTable_RMQ.test.cpp
• Test/DataStructure/DisjointSparseTable_xor.test.cpp

Code

#pragma once

#include <iostream>

namespace mtd {

  template <class S,  // set
            class op  // binary operation
            >
  requires std::is_invocable_r_v<S, op, S, S>
  struct SemiGroup {
    using value_type = S;
    using op_type = op;

    S m_val;
    constexpr SemiGroup(S val) : m_val(val) {}
    constexpr SemiGroup binaryOperation(const SemiGroup& s) const {
      return op()(m_val, s.m_val);
    }
    constexpr friend std::ostream& operator<<(std::ostream& os,
                                              const SemiGroup<S, op>& s) {
      return os << s.m_val;
    }
  };

  namespace __detail {
    template <typename T, template <typename, typename> typename S>
    concept is_semigroup_specialization_of = requires {
      typename std::enable_if_t<
          std::is_same_v<T, S<typename T::value_type, typename T::op_type>>>;
    };
  }  // namespace __detail

  template <typename G>
  concept semigroup = __detail::is_semigroup_specialization_of<G, SemiGroup>;

}  // namespace mtd

#line 2 "Library/Algebraic/SemiGroup.hpp"

#include <iostream>

namespace mtd {

  template <class S,  // set
            class op  // binary operation
            >
  requires std::is_invocable_r_v<S, op, S, S>
  struct SemiGroup {
    using value_type = S;
    using op_type = op;

    S m_val;
    constexpr SemiGroup(S val) : m_val(val) {}
    constexpr SemiGroup binaryOperation(const SemiGroup& s) const {
      return op()(m_val, s.m_val);
    }
    constexpr friend std::ostream& operator<<(std::ostream& os,
                                              const SemiGroup<S, op>& s) {
      return os << s.m_val;
    }
  };

  namespace __detail {
    template <typename T, template <typename, typename> typename S>
    concept is_semigroup_specialization_of = requires {
      typename std::enable_if_t<
          std::is_same_v<T, S<typename T::value_type, typename T::op_type>>>;
    };
  }  // namespace __detail

  template <typename G>
  concept semigroup = __detail::is_semigroup_specialization_of<G, SemiGroup>;

}  // namespace mtd

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