Dummy monoid (tools/nop_monoid.hpp)

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• Last update: 2025-02-16 14:07:51+09:00
• Include: #include "tools/nop_monoid.hpp"

struct nop_monoid {
  using T = std::monostate;
  static T op(T, T) {
    return {};
  }
  static T e() {
    return {};
  }
};

It is a dummy monoid for tools::lazy_segtree and other variants.

Constraints

• None

Time Complexity

• Not applicable

License

• CC0

Author

• anqooqie

Required by

• Dual sparse segment tree (tools/dual_sparse_segtree.hpp)
• Segment tree with lazy propagation (tools/lazy_segtree.hpp)
• Sparse segment tree with lazy propagation (tools/lazy_sparse_segtree.hpp)
• Sparse segment tree (tools/sparse_segtree.hpp)

Verified with

• tests/dual_sparse_segtree.test.cpp
• tests/lazy_segtree/dual_segtree.test.cpp
• tests/lazy_segtree/lazy_segtree/binary_search.test.cpp
• tests/lazy_segtree/lazy_segtree/prod_and_apply.test.cpp
• tests/lazy_segtree/segtree.test.cpp
• tests/lazy_sparse_segtree/binary_search.test.cpp
• tests/lazy_sparse_segtree/prod_and_apply.test.cpp
• tests/sparse_segtree.test.cpp

Code

#ifndef TOOLS_NOP_MONOID_HPP
#define TOOLS_NOP_MONOID_HPP

#include <variant>

namespace tools {
  struct nop_monoid {
    using T = ::std::monostate;
    static T op(T, T) {
      return {};
    }
    static T e() {
      return {};
    }
  };
}

#endif

#line 1 "tools/nop_monoid.hpp"



#include <variant>

namespace tools {
  struct nop_monoid {
    using T = ::std::monostate;
    static T op(T, T) {
      return {};
    }
    static T e() {
      return {};
    }
  };
}

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