std::search_n - cppreference.com

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Definido no cabeçalho `<algorithm>`

`template< class ForwardIt, class Size, class T > ForwardIt1 search_n( ForwardIt first, ForwardIt last, Size count, const T& value );`	(1)

`template< class ForwardIt, class Size, class T, class BinaryPredicate > ForwardIt1 search_n( ForwardIt first, ForwardIt last, Size count, const T& value, BinaryPredicate p );`	(2)

Pesquisas do [first, last) intervalo para a primeira seqüência de contagem de elementos idênticos, cada um igual ao valor dado valor. A primeira versão utiliza operator== para comparar os elementos, a segunda versão usa o predicado binário dado p.

Original:

Searches the range [first, last) for the first sequence of count identical elements, each equal to the given value value. The first version uses operator== to compare the elements, the second version uses the given binary predicate p.

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Parâmetros

first, last	-	a gama de elementos para examinar Original: the range of elements to examine The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
count	-	o comprimento da sequência a ser pesquisada Original: the length of the sequence to search for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
value	-	o valor dos elementos para pesquisar Original: the value of the elements to search for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
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 type `Type1` must be such that an object of type `ForwardIt` can be dereferenced and then implicitly converted to `Type1`. The type `Type2` must be such that an object of type `T` can be implicitly converted to `Type2`.
Type requirements
-`ForwardIt` must meet the requirements of `ForwardIterator`.

Valor de retorno

IIterator para o início da sequência encontrada no [first, last) gama. Se nenhuma seqüência for encontrado, é retornado last.

Original:

Iiterator to the beginning of the found sequence in the range [first, last). If no such sequence is found, last is returned.

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Complexidade

Na maioria das aplicações de last - first do predicado.

Original:

At most last - first applications of the predicate.

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Possível implementação

First version
template<class ForwardIt, class Size, class T> ForwardIt1 search_n(ForwardIt first, ForwardIt last, Size count, const T& value) { Size curr_count = 0; ForwardIt result, t_last = first; std::advance(t_last, std::distance(first, last) - count + 1); for (; first != t_last; first++) { curr_count = 0; result = first; while (*first == value) { curr_count++; if (curr_count == count) { return result; } ++first; } } return last; }
Second version
template<class ForwardIt, class Size, class T, class BinaryPredicate> ForwardIt1 search_n(ForwardIt first, ForwardIt last, Size count, const T& value, BinaryPredicate p) { Size curr_count = 0; ForwardIt result, t_last = first; std::advance(t_last, std::distance(first, last) - count + 1); for (; first != t_last; first++) { curr_count = 0; result = first; while (p(*first == value)) { curr_count++; if (curr_count == count) { return result; } ++first; } } return last; }

First version

template<class ForwardIt, class Size, class T>
ForwardIt1 search_n(ForwardIt first, ForwardIt last,
                          Size count, const T& value)
{
    Size curr_count = 0;
    ForwardIt result, t_last = first;
    std::advance(t_last, std::distance(first, last) - count + 1);
 
    for (; first != t_last; first++) {
        curr_count = 0;
        result = first;
        while (*first == value) {
            curr_count++;
            if (curr_count == count) {
                return result;
            }
            ++first;
        }
    }
    return last;
}

Second version

template<class ForwardIt, class Size, class T, class BinaryPredicate>
ForwardIt1 search_n(ForwardIt first, ForwardIt last,
                          Size count, const T& value, BinaryPredicate p)
{
    Size curr_count = 0;
    ForwardIt result, t_last = first;
    std::advance(t_last, std::distance(first, last) - count + 1);
 
    for (; first != t_last; first++) {
        curr_count = 0;
        result = first;
        while (p(*first == value)) {
            curr_count++;
            if (curr_count == count) {
                return result;
            }
            ++first;
        }
    }
    return last;
}

Exemplo

Veja também


find_end	encontra a última sequência de elementos em um determinado intervalo Original: finds the last sequence of elements in a certain range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (modelo de função) [edit]

find find_if find_if_not (C++11)	encontra o primeiro elemento satisfazer critérios específicos Original: finds the first element satisfying specific criteria The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (modelo de função) [edit]

search	searches for a range of elements (modelo de função) [edit]

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