25 Algorithms library [algorithms]

25.5 Sorting and related operations [alg.sorting]

25.5.1 Sorting [alg.sort]

25.5.1.1 sort [sort]

template<class RandomAccessIterator> void sort(RandomAccessIterator first, RandomAccessIterator last); template<class ExecutionPolicy, class RandomAccessIterator> void sort(ExecutionPolicy&& exec, RandomAccessIterator first, RandomAccessIterator last); template<class RandomAccessIterator, class Compare> void sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp); template<class ExecutionPolicy, class RandomAccessIterator, class Compare> void sort(ExecutionPolicy&& exec, RandomAccessIterator first, RandomAccessIterator last, Compare comp);

1

Requires: RandomAccessIterator shall satisfy the requirements of ValueSwappable ([swappable.requirements]). The type of *first shall satisfy the requirements of MoveConstructible (Table [tab:moveconstructible]) and of MoveAssignable (Table [tab:moveassignable]).

2

Effects: Sorts the elements in the range [first, last).

3

Complexity: Ο(Nlog(N)) comparisons, where N = last - first.

25.5.1.2 stable_sort [stable.sort]

template<class RandomAccessIterator> void stable_sort(RandomAccessIterator first, RandomAccessIterator last); template<class ExecutionPolicy, class RandomAccessIterator> void stable_sort(ExecutionPolicy&& exec, RandomAccessIterator first, RandomAccessIterator last); template<class RandomAccessIterator, class Compare> void stable_sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp); template<class ExecutionPolicy, class RandomAccessIterator, class Compare> void stable_sort(ExecutionPolicy&& exec, RandomAccessIterator first, RandomAccessIterator last, Compare comp);

1

Requires: RandomAccessIterator shall satisfy the requirements of ValueSwappable ([swappable.requirements]). The type of *first shall satisfy the requirements of MoveConstructible (Table [tab:moveconstructible]) and of MoveAssignable (Table [tab:moveassignable]).

2

Effects: Sorts the elements in the range [first, last).

3

Complexity: At most N log2(N) comparisons, where N = last - first, but only N log(N) comparisons if there is enough extra memory.

4

Remarks: Stable ([algorithm.stable]).

25.5.1.3 partial_sort [partial.sort]

template<class RandomAccessIterator> void partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last); template<class ExecutionPolicy, class RandomAccessIterator> void partial_sort(ExecutionPolicy&& exec, RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last); template<class RandomAccessIterator, class Compare> void partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last, Compare comp); template<class ExecutionPolicy, class RandomAccessIterator, class Compare> void partial_sort(ExecutionPolicy&& exec, RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last, Compare comp);

1

Requires: RandomAccessIterator shall satisfy the requirements of ValueSwappable ([swappable.requirements]). The type of *first shall satisfy the requirements of MoveConstructible (Table [tab:moveconstructible]) and of MoveAssignable (Table [tab:moveassignable]).

2

Effects: Places the first middle - first sorted elements from the range [first, last) into the range [first, middle). The rest of the elements in the range [middle, last) are placed in an unspecified order.

3

Complexity: It takes approximately (last - first) * log(middle - first) comparisons.

25.5.1.4 partial_sort_copy [partial.sort.copy]

template<class InputIterator, class RandomAccessIterator> RandomAccessIterator partial_sort_copy(InputIterator first, InputIterator last, RandomAccessIterator result_first, RandomAccessIterator result_last); template<class ExecutionPolicy, class InputIterator, class RandomAccessIterator> RandomAccessIterator partial_sort_copy(ExecutionPolicy&& exec, InputIterator first, InputIterator last, RandomAccessIterator result_first, RandomAccessIterator result_last); template<class InputIterator, class RandomAccessIterator, class Compare> RandomAccessIterator partial_sort_copy(InputIterator first, InputIterator last, RandomAccessIterator result_first, RandomAccessIterator result_last, Compare comp); template<class ExecutionPolicy, class InputIterator, class RandomAccessIterator, class Compare> RandomAccessIterator partial_sort_copy(ExecutionPolicy&& exec, InputIterator first, InputIterator last, RandomAccessIterator result_first, RandomAccessIterator result_last, Compare comp);

1

Requires: RandomAccessIterator shall satisfy the requirements of ValueSwappable ([swappable.requirements]). The type of *result_first shall satisfy the requirements of MoveConstructible (Table [tab:moveconstructible]) and of MoveAssignable (Table [tab:moveassignable]).

2

Effects: Places the first min(last - first, result_last - result_first) sorted elements into the range [result_first, result_first + min(last - first, result_last - result_first)).

3

Returns: The smaller of: result_last or result_first + (last - first).

4

Complexity: Approximately (last - first) * log(min(last - first, result_last - result_first)) comparisons.

25.5.1.5 is_sorted [is.sorted]

template<class ForwardIterator> bool is_sorted(ForwardIterator first, ForwardIterator last);

1

Returns: is_sorted_until(first, last) == last

template<class ExecutionPolicy, class ForwardIterator> bool is_sorted(ExecutionPolicy&& exec, ForwardIterator first, ForwardIterator last);

2

Returns: is_sorted_until(std::forward<ExecutionPolicy>(exec), first, last) == last

template<class ForwardIterator, class Compare> bool is_sorted(ForwardIterator first, ForwardIterator last, Compare comp);

3

Returns: is_sorted_until(first, last, comp) == last

template<class ExecutionPolicy, class ForwardIterator, class Compare> bool is_sorted(ExecutionPolicy&& exec, ForwardIterator first, ForwardIterator last, Compare comp);

4

Returns: 

is_sorted_until(std::forward<ExecutionPolicy>(exec), first, last, comp) == last

template<class ForwardIterator> ForwardIterator is_sorted_until(ForwardIterator first, ForwardIterator last); template<class ExecutionPolicy, class ForwardIterator> ForwardIterator is_sorted_until(ExecutionPolicy&& exec, ForwardIterator first, ForwardIterator last); template<class ForwardIterator, class Compare> ForwardIterator is_sorted_until(ForwardIterator first, ForwardIterator last, Compare comp); template<class ExecutionPolicy, class ForwardIterator, class Compare> ForwardIterator is_sorted_until(ExecutionPolicy&& exec, ForwardIterator first, ForwardIterator last, Compare comp);

5

Returns: If (last - first) < 2, returns last. Otherwise, returns the last iterator i in [first, last] for which the range [first, i) is sorted.

6

Complexity: Linear.