Min monoid
(Mylib/AlgebraicStructure/Monoid/min.cpp)

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

Requirements

Notes

Problems

References

Required by

• Manhattan distance MST (Mylib/Graph/MinimumSpanningTree/manhattan_minimum_spanning_tree.cpp)

Verified with

• test/aoj/1508/main.splay_tree.test.cpp
• test/aoj/1508/main.treap.test.cpp
• test/aoj/3035/main.test.cpp
• test/aoj/DSL_2_A/main.test.cpp
• test/aoj/DSL_2_F/main.dynamic.test.cpp
• test/aoj/DSL_2_F/main.test.cpp
• test/aoj/DSL_2_H/main.test.cpp
• test/yosupo-judge/manhattanmst/main.test.cpp
• test/yukicoder/875/main.test.cpp

Code

#pragma once
#include <algorithm>
#include <optional>

namespace haar_lib {
  template <typename T>
  struct min_monoid {
    using value_type = std::optional<T>;

    value_type operator()() const { return {}; }
    value_type operator()(const value_type &a, const value_type &b) const {
      if (not a) return b;
      if (not b) return a;
      return {std::min(*a, *b)};
    }
  };
}  // namespace haar_lib

#line 2 "Mylib/AlgebraicStructure/Monoid/min.cpp"
#include <algorithm>
#include <optional>

namespace haar_lib {
  template <typename T>
  struct min_monoid {
    using value_type = std::optional<T>;

    value_type operator()() const { return {}; }
    value_type operator()(const value_type &a, const value_type &b) const {
      if (not a) return b;
      if (not b) return a;
      return {std::min(*a, *b)};
    }
  };
}  // namespace haar_lib

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