With count
(Mylib/AlgebraicStructure/Monoid/with_count.cpp)

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• Last update: 2021-04-23 23:44:44+09:00

Operations

Requirements

Notes

Problems

References

Verified with

• test/aoj/3035/main.test.cpp

Code

#pragma once
#include <cstdint>
#include <utility>

namespace haar_lib {
  namespace with_count_impl {
    template <typename T>
    struct internal_value {
      T value;
      int64_t count;
      internal_value() : value(T()), count(0) {}
      internal_value(T value) : value(value), count(1) {}
      internal_value(T value, int64_t count) : value(value), count(count) {}
    };
  }  // namespace with_count_impl

  template <typename Monoid>
  struct with_count {
    using value_type = with_count_impl::internal_value<typename Monoid::value_type>;
    const static Monoid M;

    value_type operator()() const {
      return {M(), 0};
    }

    value_type operator()(const value_type &a, const value_type &b) const {
      if (a.value == b.value) return {a.value, a.count + b.count};
      if (M(a.value, b.value) == a.value) return a;
      return b;
    }
  };
}  // namespace haar_lib

#line 2 "Mylib/AlgebraicStructure/Monoid/with_count.cpp"
#include <cstdint>
#include <utility>

namespace haar_lib {
  namespace with_count_impl {
    template <typename T>
    struct internal_value {
      T value;
      int64_t count;
      internal_value() : value(T()), count(0) {}
      internal_value(T value) : value(value), count(1) {}
      internal_value(T value, int64_t count) : value(value), count(count) {}
    };
  }  // namespace with_count_impl

  template <typename Monoid>
  struct with_count {
    using value_type = with_count_impl::internal_value<typename Monoid::value_type>;
    const static Monoid M;

    value_type operator()() const {
      return {M(), 0};
    }

    value_type operator()(const value_type &a, const value_type &b) const {
      if (a.value == b.value) return {a.value, a.count + b.count};
      if (M(a.value, b.value) == a.value) return a;
      return b;
    }
  };
}  // namespace haar_lib

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