ceph/src/boost/libs/range/doc/reference/algorithm/prev_permutation.qbk

   1 [/
   2     Copyright 2010 Neil Groves
   3     Distributed under the Boost Software License, Version 1.0.
   4     (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5 /]
   6 [section:prev_permutation prev_permutation]
   7
   8 [heading Prototype]
   9
  10 ``
  11 template<class BidirectionalRange>
  12 bool prev_permutation(BidirectionalRange& rng);
  13
  14 template<class BidirectionalRange>
  15 bool prev_permutation(const BidirectionalRange& rng);
  16
  17 template<class BidirectionalRange, class Compare>
  18 bool prev_permutation(BidirectionalRange& rng, Compare pred);
  19
  20 template<class BidirectionalRange, class Compare>
  21 bool prev_permutation(const BidirectionalRange& rng, Compare pred);
  22 ``
  23
  24 [heading Description]
  25
  26 `prev_permutation` transforms the range of elements `rng` into the lexicographically next smaller permutation of the elements if such a permutation exists. If one does not exist then the range is transformed into the lexicographically largest permutation and `false` is returned. `true` is returned when the next smaller permutation is successfully generated.
  27
  28 The ordering relationship is determined by using `operator<` in the non-predicate versions, and by evaluating `pred` in the predicate versions.
  29
  30 [heading Definition]
  31
  32 Defined in the header file `boost/range/algorithm/permutation.hpp`
  33
  34 [heading Requirements]
  35
  36 [*For the non-predicate versions:]
  37
  38 * `BidirectionalRange` is a model of the __bidirectional_range__ Concept.
  39 * `BidirectionalRange` is mutable.
  40 * `BidirectionalRange`'s value type is a model of the `LessThanComparableConcept`.
  41 * The ordering of objects of type `BidirectionalRange`'s value type is a [*/strict weak ordering/], as defined in the `LessThanComparableConcept` requirements.
  42
  43 [*For the predicate versions:]
  44
  45 * `BidirectionalRange` is a model of the __bidirectional_range__ Concept.
  46 * `BidirectionalRange` is mutable.
  47 * `Compare` is a model of the `StrictWeakOrderingConcept`.
  48 * `BidirectionalRange`'s value type is convertible to both of `Compare`'s argument types.
  49
  50 [heading Complexity]
  51
  52 Linear. At most `distance(rng) / 2` swaps.
  53
  54 [endsect]
  55
  56