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partial_sort_copy.hpp
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1 // Range v3 library
3 //
4 // Copyright Eric Niebler 2013-present
5 //
6 // Use, modification and distribution is subject to the
7 // Boost Software License, Version 1.0. (See accompanying
8 // file LICENSE_1_0.txt or copy at
9 // http://www.boost.org/LICENSE_1_0.txt)
10 //
11 // Project home: https://github.com/ericniebler/range-v3
12 //
13 #ifndef RANGES_V3_ALGORITHM_PARTIAL_SORT_COPY_HPP
14 #define RANGES_V3_ALGORITHM_PARTIAL_SORT_COPY_HPP
15 
16 #include <meta/meta.hpp>
17 
18 #include <range/v3/range_fwd.hpp>
19 
30 #include <range/v3/utility/static_const.hpp>
31 
32 #include <range/v3/detail/prologue.hpp>
33 
34 namespace ranges
35 {
38  RANGES_FUNC_BEGIN(partial_sort_copy)
39 
40 
41  template(typename I,
42  typename SI,
43  typename O,
44  typename SO,
45  typename C = less,
46  typename PI = identity,
47  typename PO = identity)(
48  requires input_iterator<I> AND sentinel_for<SI, I> AND
49  random_access_iterator<O> AND sentinel_for<SO, O> AND
50  indirectly_copyable<I, O> AND sortable<O, C, PO> AND
51  indirect_strict_weak_order<C, projected<I, PI>, projected<O, PO>>)
52  constexpr O RANGES_FUNC(partial_sort_copy)(I first,
53  SI last,
54  O out_begin,
55  SO out_end,
56  C pred = C{},
57  PI in_proj = PI{},
58  PO out_proj = PO{}) //
59  {
60  O r = out_begin;
61  if(r != out_end)
62  {
63  for(; first != last && r != out_end; ++first, ++r)
64  *r = *first;
65  make_heap(out_begin, r, ranges::ref(pred), ranges::ref(out_proj));
66  auto len = r - out_begin;
67  for(; first != last; ++first)
68  {
69  auto && x = *first;
70  if(invoke(pred, invoke(in_proj, x), invoke(out_proj, *out_begin)))
71  {
72  *out_begin = (decltype(x) &&)x;
73  detail::sift_down_n(out_begin,
74  len,
75  out_begin,
76  ranges::ref(pred),
77  ranges::ref(out_proj));
78  }
79  }
80  sort_heap(out_begin, r, ranges::ref(pred), ranges::ref(out_proj));
81  }
82  return r;
83  }
84 
86  template(typename InRng,
87  typename OutRng,
88  typename C = less,
89  typename PI = identity,
90  typename PO = identity)(
91  requires input_range<InRng> AND random_access_range<OutRng> AND
93  sortable<iterator_t<OutRng>, C, PO> AND
95  projected<iterator_t<InRng>, PI>,
96  projected<iterator_t<OutRng>, PO>>)
97  constexpr borrowed_iterator_t<OutRng> RANGES_FUNC(partial_sort_copy)(InRng && in_rng,
98  OutRng && out_rng,
99  C pred = C{},
100  PI in_proj = PI{},
101  PO out_proj = PO{}) //
102  {
103  return (*this)(begin(in_rng),
104  end(in_rng),
105  begin(out_rng),
106  end(out_rng),
107  std::move(pred),
108  std::move(in_proj),
109  std::move(out_proj));
110  }
111 
112  RANGES_FUNC_END(partial_sort_copy)
113 
114  namespace cpp20
115  {
116  using ranges::partial_sort_copy;
117  }
119 } // namespace ranges
120 
121 #include <range/v3/detail/epilogue.hpp>
122 
123 #endif
template(typename InRng, typename OutRng, typename C=less, typename PI=identity, typename PO=identity)(requires input_range< InRng > AND random_access_range< OutRng > AND indirectly_copyable< iterator_t< InRng >
This is an overloaded member function, provided for convenience. It differs from the above function o...
CPP_concept sentinel_for
\concept sentinel_for
Definition: concepts.hpp:306
CPP_concept input_iterator
\concept input_iterator
Definition: concepts.hpp:362
CPP_concept sortable
\concept sortable
Definition: concepts.hpp:865
CPP_concept indirect_strict_weak_order
\concept indirect_strict_weak_order
Definition: concepts.hpp:689
CPP_concept random_access_iterator
\concept random_access_iterator
Definition: concepts.hpp:416
CPP_concept indirectly_copyable
\concept indirectly_copyable
Definition: concepts.hpp:782
decltype(begin(declval(Rng &))) iterator_t
Definition: access.hpp:698
typename Fn::template invoke< Args... > invoke
Evaluate the invocable Fn with the arguments Args.
Definition: meta.hpp:541
front< Pair > first
Retrieve the first element of the pair Pair.
Definition: meta.hpp:2251
bool_<(T::type::value< U::type::value)> less
A Boolean integral constant wrapper around true if T::type::value is less than U::type::value; false,...
Definition: meta.hpp:255
Tiny meta-programming library.
Definition: identity.hpp:25
Definition: comparisons.hpp:50