一次関数の合成を得る演算のモノイド (utility/monoid/composite.cpp)

/**
 * @brief 一次関数の合成を得る演算のモノイド
 * @author えびちゃん
 */

#include <algorithm>
#include <utility>

#ifndef H_composite_monoid
#define H_composite_monoid

template <typename Tp>
class composite_monoid {
public:
  using value_type = Tp;

private:
  value_type M_a = 1;
  value_type M_b = 0;

public:
  composite_monoid() = default;  // identity

  composite_monoid(value_type a, value_type b): M_a(a), M_b(b) {};

  composite_monoid& operator +=(composite_monoid that) {
    M_a *= that.M_a;
    M_b *= that.M_a;
    M_b += that.M_b;
    return *this;
  }

  composite_monoid operator +(composite_monoid const& that) const {
    return composite_monoid(*this) += that;
  }
  composite_monoid operator +(composite_monoid&& that) const {
    return composite_monoid(*this) += std::move(that);
  }

  bool operator ==(composite_monoid const& that) const {
    return (M_a == that.M_a && M_b == that.M_b);
  }
  bool operator !=(composite_monoid const& that) const { return !(*this == that); }

  auto get() const { return std::make_pair(M_a, M_b); }
  value_type operator ()(value_type x) const { return M_a * x + M_b; }
};

#endif  /* !defined(H_composite_monoid) */

#line 1 "utility/monoid/composite.cpp"
/**
 * @brief 一次関数の合成を得る演算のモノイド
 * @author えびちゃん
 */

#include <algorithm>
#include <utility>

#ifndef H_composite_monoid
#define H_composite_monoid

template <typename Tp>
class composite_monoid {
public:
  using value_type = Tp;

private:
  value_type M_a = 1;
  value_type M_b = 0;

public:
  composite_monoid() = default;  // identity

  composite_monoid(value_type a, value_type b): M_a(a), M_b(b) {};

  composite_monoid& operator +=(composite_monoid that) {
    M_a *= that.M_a;
    M_b *= that.M_a;
    M_b += that.M_b;
    return *this;
  }

  composite_monoid operator +(composite_monoid const& that) const {
    return composite_monoid(*this) += that;
  }
  composite_monoid operator +(composite_monoid&& that) const {
    return composite_monoid(*this) += std::move(that);
  }

  bool operator ==(composite_monoid const& that) const {
    return (M_a == that.M_a && M_b == that.M_b);
  }
  bool operator !=(composite_monoid const& that) const { return !(*this == that); }

  auto get() const { return std::make_pair(M_a, M_b); }
  value_type operator ()(value_type x) const { return M_a * x + M_b; }
};

#endif  /* !defined(H_composite_monoid) */