26 Algorithms library [algorithms]

26.7 Mutating sequence operations [alg.modifying.operations]

26.7.11 Rotate [alg.rotate]

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template<class ForwardIterator> constexpr ForwardIterator rotate(ForwardIterator first, ForwardIterator middle, ForwardIterator last); template<class ExecutionPolicy, class ForwardIterator> ForwardIterator rotate(ExecutionPolicy&& exec, ForwardIterator first, ForwardIterator middle, ForwardIterator last); template<permutable I, sentinel_for<I> S> constexpr subrange<I> ranges::rotate(I first, I middle, S last); template<execution-policy Ep, random_access_iterator I, sized_sentinel_for<I> S> requires permutable<I> subrange<I> ranges::rotate(Ep&& exec, I first, I middle, S last);
1
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Preconditions: [first, middle) and [middle, last) are valid ranges.
For the overloads in namespace std, ForwardIterator meets the Cpp17ValueSwappable requirements ([swappable.requirements]), and the type of *first meets the Cpp17MoveConstructible (Table 31) and Cpp17MoveAssignable (Table 33) requirements.
2
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Effects: For each non-negative integer i < (last - first), places the element from the position first + i into position first + (i + (last - middle)) % (last - first).
[Note 1: 
This is a left rotate.
— end note]
3
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Returns:
  • (3.1)
    first + (last - middle) for the overloads in namespace std.
  • (3.2)
    {first + (last - middle), last} for the overload in namespace ranges.
4
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Complexity: At most last - first swaps.
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template<forward_range R> requires permutable<iterator_t<R>> constexpr borrowed_subrange_t<R> ranges::rotate(R&& r, iterator_t<R> middle);
5
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Effects: Equivalent to: return ranges​::​rotate(ranges​::​begin(r), middle, ranges​::​end(r));
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template<execution-policy Ep, sized-random-access-range R> requires permutable<iterator_t<R>> borrowed_subrange_t<R> ranges::rotate(Ep&& exec, R&& r, iterator_t<R> middle);
6
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Effects: Equivalent to: return ranges::rotate(std::forward<Ep>(exec), ranges::begin(r), middle, ranges::end(r));
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template<class ForwardIterator, class OutputIterator> constexpr OutputIterator rotate_copy(ForwardIterator first, ForwardIterator middle, ForwardIterator last, OutputIterator result); template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2> ForwardIterator2 rotate_copy(ExecutionPolicy&& exec, ForwardIterator1 first, ForwardIterator1 middle, ForwardIterator1 last, ForwardIterator2 result); template<forward_iterator I, sentinel_for<I> S, weakly_incrementable O> requires indirectly_copyable<I, O> constexpr ranges::rotate_copy_result<I, O> ranges::rotate_copy(I first, I middle, S last, O result);
7
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Let N be last - first.
8
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Preconditions: [first, middle) and [middle, last) are valid ranges.
The ranges [first, last) and [result, result + N) do not overlap.
9
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Effects: Copies the range [first, last) to the range [result, result + N) such that for each non-negative integer the following assignment takes place: *(result + i) = *(first + (i + (middle - first)) % N).
10
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Returns:
  • (10.1)
    result + N for the overloads in namespace std.
  • (10.2)
    {last, result + N} for the overload in namespace ranges.
11
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Complexity: Exactly N assignments.
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template<execution-policy Ep, random_access_iterator I, sized_sentinel_for<I> S, random_access_iterator O, sized_sentinel_for<O> OutS> requires indirectly_copyable<I, O> ranges::rotate_copy_truncated_result<I, O> ranges::rotate_copy(Ep&& exec, I first, I middle, S last, O result, OutS result_last);
12
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Let M be last - first and N be min(M,  result_last - result).
13
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Preconditions: [first, middle) and [middle, last) are valid ranges.
The ranges [first, last) and [result, result + N) do not overlap.
14
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Effects: Copies the range [first, last) to the range [result, result + N) such that for each non-negative integer the following assignment takes place: *(result + i) = *(first + (i + (middle - first)) % M).
15
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Returns:
  • (15.1)
    {middle + N, first, result + N} if N is less than last - middle.
  • (15.2)
    Otherwise, {last, first + (N + (middle - first)) % M, result + N}.
16
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Complexity: Exactly N assignments.
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template<forward_range R, weakly_incrementable O> requires indirectly_copyable<iterator_t<R>, O> constexpr ranges::rotate_copy_result<borrowed_iterator_t<R>, O> ranges::rotate_copy(R&& r, iterator_t<R> middle, O result);
17
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Effects: Equivalent to: return ranges::rotate_copy(ranges::begin(r), middle, ranges::end(r), std::move(result));
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template<execution-policy Ep, sized-random-access-range R, sized-random-access-range OutR> requires indirectly_copyable<iterator_t<R>, iterator_t<OutR>> ranges::rotate_copy_truncated_result<borrowed_iterator_t<R>, borrowed_iterator_t<OutR>> ranges::rotate_copy(Ep&& exec, R&& r, iterator_t<R> middle, OutR&& result_r);
18
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Effects: Equivalent to: return ranges::rotate_copy(std::forward<Ep>(exec), ranges::begin(r), middle, ranges::end(r), ranges::begin(result_r), ranges::end(result_r));