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std::minmax - cppreference.com

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Definido no cabeçalho

<algorithm>

template< class T > std::pair<const T&,const T&> minmax( const T& a, const T& b );

(1) (desde C++11)

template< class T, class Compare > std::pair<const T&,const T&> minmax( const T& a, const T& b, Compare comp );

(2) (desde C++11)

template< class T > std::pair<T,T> minmax( std::initializer_list<T> ilist);

(3) (desde C++11)

template< class T, class Compare > std::pair<T,T> minmax( std::initializer_list<T> ilist, Compare comp );

(4) (desde C++11)

1-2)

Retorna o menor e o maior dos dois valores.

Original:

Returns the smaller and the greater of the two values.

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3-4)

Retorna a lista menor e maior dos valores em inicializador ilist.

Original:

Returns the smallest and the greatest of the values in initializer list ilist.

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As versões (1,3) usa operator< para comparar os valores, enquanto que as versões (2,4) utilizar a função de comparação dada comp.

Original:

The (1,3) versions use operator< to compare the values, whereas the (2,4) versions use the given comparison function comp.

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Parâmetros

a, b -

os valores para comparar

Original:

the values to compare

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ilist -

inicializador lista com os valores para comparar

Original:

initializer list with the values to compare

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comp - comparison function which returns ​true if if a is less than b.

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

bool cmp(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 T can be implicitly converted to both of them. ​

Type requirements
-T must meet the requirements of LessThanComparable. for the overloads (1) and (3)
-T must meet the requirements of CopyConstructible. for the overloads (3) and (4)

Valor de retorno

1-2)

Retorna o resultado de se std::make_pair(a, b) a<b ou se a é equivalente a b. Retorna o resultado da std::make_pair(b, a) se b<a.

Original:

Returns the result of std::make_pair(a, b) if a<b or if a is equivalent to b. Returns the result of std::make_pair(b, a) if b<a.

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3-4)

A par com o menor valor na ilist como o primeiro elemento e maior que a segunda. Se vários elementos são equivalentes a menor, o elemento mais à esquerda como é retornado. Se vários elementos são equivalentes ao maior, o elemento mais à direita são devolvidas.

Original:

A pair with the smallest value in ilist as the first element and the greatest as the second. If several elements are equivalent to the smallest, the leftmost such element is returned. If several elements are equivalent to the largest, the rightmost such element is returned.

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Complexidade

1-2)

Constante

Original:

Constant

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3-4)

Linear em ilist.size()

Original:

Linear in ilist.size()

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Possível implementação

First version
template<class T> 
std::pair<const T&,const T&> minmax(const T& a, const T& b)
{
    return (b < a) ? std::make_pair(b, a)
                   : std::make_pair(a, b);
}
Second version
template<class T, class Compare> 
std::pair<const T&,const T&> minmax(const T& a, const T& b, Compare comp)
{
    return comp(b, a) ? std::make_pair(b, a)
                      : std::make_pair(a, b);
}
Third version
template< class T >
std::pair<T,T> minmax( std::initializer_list ilist)
{
    auto p = std::minmax_element(ilist.begin(), ilist.end());
    return std::make_pair(*p.first, *p.second);
}
Fourth version
template< class T, class Compare >
std::pair<T,T> minmax( std::initializer_list ilist, Compare comp )
{
    auto p = std::minmax_element(ilist.begin(), ilist.end(), comp);
    return std::make_pair(*p.first, *p.second);
}

Exemplo

#include <algorithm>
#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>

int main()
{
    std::vector<int> v {3, 1, 4, 1, 5, 9, 2, 6}; 
    std::srand(std::time(0));
    std::pair<int,int> bounds = std::minmax(std::rand() % v.size(),
                                            std::rand() % v.size());

    std::cout << "v[" << bounds.first << "," << bounds.second << "]: ";
    for (int i = bounds.first; i < bounds.second; ++i) {
        std::cout << v[i] << ' ';
    }
    std::cout << '\n';
}

Potencial saída:

Veja também

retorna o menor dos dois elementos

Original:

returns the smaller of two elements

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(modelo de função) [edit]

devolve o maior dos dois elementos

Original:

returns the larger of two elements

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(modelo de função) [edit]