libstdc++
eq_by_less.hpp
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1 // -*- C++ -*-
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3 // Copyright (C) 2005-2014 Free Software Foundation, Inc.
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25 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
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35 
36 /**
37  * @file eq_by_less.hpp
38  * Contains an equivalence function.
39  */
40 
41 #ifndef PB_DS_EQ_BY_LESS_HPP
42 #define PB_DS_EQ_BY_LESS_HPP
43 
44 #include <utility>
45 #include <functional>
46 #include <vector>
47 #include <assert.h>
49 
50 namespace __gnu_pbds
51 {
52  namespace detail
53  {
54  /// Equivalence function.
55  template<typename Key, class Cmp_Fn>
56  struct eq_by_less : private Cmp_Fn
57  {
58  bool
59  operator()(const Key& r_lhs, const Key& r_rhs) const
60  {
61  const bool l = Cmp_Fn::operator()(r_lhs, r_rhs);
62  const bool g = Cmp_Fn::operator()(r_rhs, r_lhs);
63  return !(l || g);
64  }
65  };
66  } // namespace detail
67 } // namespace __gnu_pbds
68 
69 #endif // #ifndef PB_DS_EQ_BY_LESS_HPP
Equivalence function.
Definition: eq_by_less.hpp:56