Difference between revisions of "cpp/algorithm/minmax"

Revision as of 04:12, 3 July 2012

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<td > (1) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td > (2) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td > (3) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td > (4) </td> <td > (since C++11) </td> </tr> Template:ddcl list end

1-2) Returns the smaller and the greater of the two values.

3-4) Returns the smallest and the greatest of the values in initializer list ilist.

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

Parameters

Return value

1-2) 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.

3-4) 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.

Complexity

1-2) Constant

3-4) Linear in ilist.size()

Possible implementation

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);
}

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);
}

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);
}

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);
}

Example

See also