template<class ForwardIterator>
ForwardIterator unique(ForwardIterator first, ForwardIterator last);
template<class ExecutionPolicy, class ForwardIterator>
ForwardIterator unique(ExecutionPolicy&& exec,
ForwardIterator first, ForwardIterator last);
template<class ForwardIterator, class BinaryPredicate>
ForwardIterator unique(ForwardIterator first, ForwardIterator last,
BinaryPredicate pred);
template<class ExecutionPolicy, class ForwardIterator, class BinaryPredicate>
ForwardIterator unique(ExecutionPolicy&& exec,
ForwardIterator first, ForwardIterator last,
BinaryPredicate pred);
Requires: The comparison function shall be an equivalence relation. The type of *first shall satisfy the MoveAssignable requirements (Table [tab:moveassignable]).
Effects: For a nonempty range, eliminates all but the first element from every consecutive group of equivalent elements referred to by the iterator i in the range [first + 1, last) for which the following conditions hold: *(i - 1) == *i or pred(*(i - 1), *i) != false.
Returns: The end of the resulting range.
Complexity: For nonempty ranges, exactly (last - first) - 1 applications of the corresponding predicate.
template<class InputIterator, class OutputIterator>
OutputIterator
unique_copy(InputIterator first, InputIterator last,
OutputIterator result);
template<class ExecutionPolicy, class InputIterator, class OutputIterator>
OutputIterator
unique_copy(ExecutionPolicy&& exec,
InputIterator first, InputIterator last,
OutputIterator result);
template<class InputIterator, class OutputIterator,
class BinaryPredicate>
OutputIterator
unique_copy(InputIterator first, InputIterator last,
OutputIterator result, BinaryPredicate pred);
template<class ExecutionPolicy, class InputIterator, class OutputIterator,
class BinaryPredicate>
OutputIterator
unique_copy(ExecutionPolicy&& exec,
InputIterator first, InputIterator last,
OutputIterator result, BinaryPredicate pred);
Requires: The comparison function shall be an equivalence relation. The ranges [first, last) and [result, result+(last-first)) shall not overlap. The expression *result = *first shall be valid. Let T be the value type of InputIterator. If InputIterator meets the forward iterator requirements, then there are no additional requirements for T. Otherwise, if OutputIterator meets the forward iterator requirements and its value type is the same as T, then T shall be CopyAssignable (Table [tab:copyassignable]). Otherwise, T shall be both CopyConstructible (Table [tab:copyconstructible]) and CopyAssignable.
Effects: Copies only the first element from every consecutive group of equal elements referred to by the iterator i in the range [first, last) for which the following corresponding conditions hold: *i == *(i - 1) or pred(*i, *(i - 1)) != false.
Returns: The end of the resulting range.
Complexity: For nonempty ranges, exactly last - first - 1 applications of the corresponding predicate.