Namespace
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std::unique

Da cppreference.com.
< cpp‎ | algorithm

 
 
Algoritmo libreria
Funzioni
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Functions
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Non modifica le operazioni di sequenza
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Non-modifying sequence operations
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Modifica delle operazioni di sequenza
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Modifying sequence operations
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Partizionamento operazioni
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Partitioning operations
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Ordinamento delle operazioni (su intervalli ordinati)
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Sorting operations (on sorted ranges)
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Binarie (le operazioni di ricerca sui campi ordinati)
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Binary search operations (on sorted ranges)
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Impostare le operazioni (su intervalli ordinati)
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Set operations (on sorted ranges)
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Heap operazioni
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Heap operations
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Minimo / massimo le operazioni
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Minimum/maximum operations
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Operazioni numeriche
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Numeric operations
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Libreria C
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C library
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Defined in header <algorithm>
template< class ForwardIt >
ForwardIt unique( ForwardIt first, ForwardIt last );
(1)
template< class ForwardIt, class BinaryPredicate >
ForwardIt unique( ForwardIt first, ForwardIt last, BinaryPredicate p );
(2)
Rimuove tutti gli elementi duplicati consecutivi dal [first, last) gamma. Rimozione avviene spostando la gamma quando necessario in modo tale che gli elementi da cancellare vengono sovrascritti. Solo il primo elemento in ciascun gruppo di elementi uguali viene lasciato. Gli elementi tra la vecchia e la nuova estremità o la gamma vengono lasciati intatti. La prima versione utilizza operator== di confrontare gli elementi, la seconda versione utilizza il predicato binario dato p.
Original:
Removes all consecutive duplicate elements from the range [first, last). Removing is done by shifting the range when needed in such a way that elements to be erased are overwritten. Only the first element in each group of equal elements is left. The elements between the old and the new end or the range are left intact. The first version uses operator== to compare the elements, the second version uses the given binary predicate p.
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Indice

[modifica] Parametri

first, last -
l'intervallo di elementi di processo
Original:
the range of elements to process
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p - binary predicate which returns ​true if the elements should be treated as equal.

The signature of the predicate function should be equivalent to the following:

 bool pred(const Type1 &a, const Type2 &b);

The signature does not need to have const &, but the function must not modify the objects passed to it.
The types  Type1 and  Type2 must be such that an object of type ForwardIt can be dereferenced and then implicitly converted to both of them.

Type requirements
-
ForwardIt must meet the requirements of ForwardIterator.
-
The type of dereferenced ForwardIt must meet the requirements of MoveAssignable.

[modifica] Valore di ritorno

Inoltra iteratore alla fine nuovo della gamma
Original:
Forward iterator to the new end of the range
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[modifica] Possibile implementazione

First version
template<class ForwardIt>
ForwardIt unique(ForwardIt first, ForwardIt last)
{
    if (first == last)
        return last;
 
    ForwardIt result = first;
    while (++first != last) {
        if (!(*result == *first)) {
            *(++result) = *first;
        }
    }
    return ++result;
}
Second version
template<class ForwardIt, class BinaryPredicate>
ForwardIt unique(ForwardIt first, ForwardIt last, 
                       BinaryPredicate p)
{
    if (first == last)
        return last;
 
    ForwardIt result = first;
    while (++first != last) {
        if (!p(*result, *first)) {
            *(++result) = *first;
        }
    }
    return ++result;
}

[modifica] Esempio

Il codice seguente rimuove tutti gli elementi consecutivi equivalenti da un vettore di interi .
Original:
The following code removes all consecutive equivalent elements from a vector of integers.
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#include <iostream>
#include <algorithm>
#include <vector>
 
int main() 
{
    std::vector<int> v{1, 2, 2, 2, 3, 3, 2, 2, 1};
    std::vector<int>::iterator last;
 
    last = std::unique(v.begin(), v.end()); // 1 2 3 2 1 3 2 2 1
                                            //           ^
    for (std::vector<int>::iterator it = v.begin(); it != last; ++it) {
        std::cout << *it << " ";
    }
    std::cout << "\n";
}

Output:

1 2 3 2 1

[modifica] Complessità

lineare la distanza tra first e last
Original:
linear in the distance between first and last
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[modifica] Vedi anche

trova due identici (o qualche altra relazione) elementi adiacenti l'uno all'altro
Original:
finds two identical (or some other relationship) items adjacent to each other
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(funzione di modello) [edit]
crea una copia di alcune serie di elementi che non contiene duplicati consecutivi
Original:
creates a copy of some range of elements that contains no consecutive duplicates
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(funzione di modello) [edit]