128 lines
6.4 KiB
Markdown
128 lines
6.4 KiB
Markdown
[alg.is.permutation]
|
||
|
||
# 26 Algorithms library [[algorithms]](./#algorithms)
|
||
|
||
## 26.6 Non-modifying sequence operations [[alg.nonmodifying]](alg.nonmodifying#alg.is.permutation)
|
||
|
||
### 26.6.14 Is permutation [alg.is.permutation]
|
||
|
||
[ð](#lib:is_permutation)
|
||
|
||
`template<class ForwardIterator1, class ForwardIterator2>
|
||
constexpr bool is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
|
||
ForwardIterator2 first2);
|
||
template<class ForwardIterator1, class ForwardIterator2,
|
||
class BinaryPredicate>
|
||
constexpr bool is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
|
||
ForwardIterator2 first2, BinaryPredicate pred);
|
||
template<class ForwardIterator1, class ForwardIterator2>
|
||
constexpr bool is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
|
||
ForwardIterator2 first2, ForwardIterator2 last2);
|
||
template<class ForwardIterator1, class ForwardIterator2,
|
||
class BinaryPredicate>
|
||
constexpr bool is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
|
||
ForwardIterator2 first2, ForwardIterator2 last2,
|
||
BinaryPredicate pred);
|
||
`
|
||
|
||
[1](#1)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/algorithms.tex#L5722)
|
||
|
||
Let last2 be first2 + (last1 - first1) for the overloads with no parameter named last2,
|
||
and let pred be equal_to{} for the overloads with no parameter pred[.](#1.sentence-1)
|
||
|
||
[2](#2)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/algorithms.tex#L5728)
|
||
|
||
*Mandates*: ForwardIterator1 and ForwardIterator2 have the same value type[.](#2.sentence-1)
|
||
|
||
[3](#3)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/algorithms.tex#L5732)
|
||
|
||
*Preconditions*: The comparison function is an equivalence relation[.](#3.sentence-1)
|
||
|
||
[4](#4)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/algorithms.tex#L5736)
|
||
|
||
*Returns*: If last1 - first1 != last2 - first2, return false[.](#4.sentence-1)
|
||
|
||
Otherwise return true if there exists a permutation of the elements
|
||
in the range [first2, last2),
|
||
beginning with ForwardIterator2 begin,
|
||
such that equal(first1, last1, begin, pred) returns true;
|
||
otherwise, returns false[.](#4.sentence-2)
|
||
|
||
[5](#5)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/algorithms.tex#L5746)
|
||
|
||
*Complexity*: No applications of the corresponding predicate
|
||
if ForwardIterator1 and ForwardIterator2 meet the requirements of random access iterators andlast1 - first1 != last2 - first2[.](#5.sentence-1)
|
||
|
||
Otherwise, exactly last1 - first1 applications
|
||
of the corresponding predicate
|
||
if equal(first1, last1, first2, last2, pred) would return true;
|
||
otherwise, at worst O(N2), where N has the value last1 - first1[.](#5.sentence-2)
|
||
|
||
[ð](#lib:is_permutation_)
|
||
|
||
`template<[forward_iterator](iterator.concept.forward#concept:forward_iterator "24.3.4.11 Concept forward_iterator [iterator.concept.forward]") I1, [sentinel_for](iterator.concept.sentinel#concept:sentinel_for "24.3.4.7 Concept sentinel_for [iterator.concept.sentinel]")<I1> S1, [forward_iterator](iterator.concept.forward#concept:forward_iterator "24.3.4.11 Concept forward_iterator [iterator.concept.forward]") I2,
|
||
[sentinel_for](iterator.concept.sentinel#concept:sentinel_for "24.3.4.7 Concept sentinel_for [iterator.concept.sentinel]")<I2> S2, class Proj1 = identity, class Proj2 = identity,
|
||
[indirect_equivalence_relation](indirectcallable.indirectinvocable#concept:indirect_equivalence_relation "24.3.6.3 Indirect callables [indirectcallable.indirectinvocable]")<projected<I1, Proj1>,
|
||
projected<I2, Proj2>> Pred = ranges::equal_to>
|
||
constexpr bool ranges::is_permutation(I1 first1, S1 last1, I2 first2, S2 last2,
|
||
Pred pred = {},
|
||
Proj1 proj1 = {}, Proj2 proj2 = {});
|
||
template<[forward_range](range.refinements#concept:forward_range "25.4.6 Other range refinements [range.refinements]") R1, [forward_range](range.refinements#concept:forward_range "25.4.6 Other range refinements [range.refinements]") R2,
|
||
class Proj1 = identity, class Proj2 = identity,
|
||
[indirect_equivalence_relation](indirectcallable.indirectinvocable#concept:indirect_equivalence_relation "24.3.6.3 Indirect callables [indirectcallable.indirectinvocable]")<projected<iterator_t<R1>, Proj1>,
|
||
projected<iterator_t<R2>, Proj2>> Pred = ranges::equal_to>
|
||
constexpr bool ranges::is_permutation(R1&& r1, R2&& r2, Pred pred = {},
|
||
Proj1 proj1 = {}, Proj2 proj2 = {});
|
||
`
|
||
|
||
[6](#6)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/algorithms.tex#L5776)
|
||
|
||
*Returns*: If last1 - first1 != last2 - first2, return false[.](#6.sentence-1)
|
||
|
||
Otherwise return true if there exists a permutation of the elements
|
||
in the range [first2, last2), bounded by [pfirst, plast),
|
||
such thatranges::equal(first1, last1, pfirst, plast, pred, proj1, proj2) returns true;
|
||
otherwise, returns false[.](#6.sentence-2)
|
||
|
||
[7](#7)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/algorithms.tex#L5786)
|
||
|
||
*Complexity*: No applications of the corresponding predicate and projections if
|
||
|
||
- [(7.1)](#7.1)
|
||
|
||
for the first overload,
|
||
* [(7.1.1)](#7.1.1)
|
||
|
||
S1 and I1 model [sized_sentinel_for](iterator.concept.sizedsentinel#concept:sized_sentinel_for "24.3.4.8 Concept sized_sentinel_for [iterator.concept.sizedsentinel]")<S1, I1>,
|
||
|
||
* [(7.1.2)](#7.1.2)
|
||
|
||
S2 and I2 model [sized_sentinel_for](iterator.concept.sizedsentinel#concept:sized_sentinel_for "24.3.4.8 Concept sized_sentinel_for [iterator.concept.sizedsentinel]")<S2, I2>, and
|
||
|
||
* [(7.1.3)](#7.1.3)
|
||
|
||
last1 - first1 != last2 - first2;
|
||
|
||
- [(7.2)](#7.2)
|
||
|
||
for the second overload,R1 and R2 each model [sized_range](range.sized#concept:sized_range "25.4.4 Sized ranges [range.sized]"), andranges::distance(r1) != ranges::distance(r2)[.](#7.sentence-1)
|
||
|
||
Otherwise, exactly last1 - first1 applications
|
||
of the corresponding predicate and projections
|
||
if ranges::equal(first1, last1, first2, last2, pred, proj1, proj2) would return true;
|
||
otherwise, at worst O(N2), where N has the value last1 - first1[.](#7.sentence-2)
|