Difference between revisions of "cpp/algorithm/minmax"
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(equivalence, and functions) |
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| Line 35: | Line 35: | ||
===Return value=== | ===Return value=== | ||
| − | 1-2) | + | 1-2) Returns the result of {{cpp|std::make_pair(a, b)}} if {{tt|a<b}} or if {{tt|a}} is equivalent to {{tt|b}}. Returns the result of {cpp|std::make_pair(b, a)}} if {{tt|b<a}}. |
| − | 3-4) A pair with the smallest value in {{tt|ilist}} as the first element and the greatest as the second. | + | 3-4) A pair with the smallest value in {{tt|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=== | ===Complexity=== | ||
1-2) {{complex constant}} | 1-2) {{complex constant}} | ||
| − | 3-4) {{ | + | 3-4) Linear in {{tt|ilist.size()}} |
===Equivalent function=== | ===Equivalent function=== | ||
| − | + | {{eq fun cpp | |
| 1= | | 1= | ||
template<class T> | template<class T> | ||
std::pair<const T&,const T&> minmax(const T& a, const T& b) | std::pair<const T&,const T&> minmax(const T& a, const T& b) | ||
{ | { | ||
| − | return | + | return b < a) ? std::make_pair(b, a) |
| + | : std::make_pair(a, b); | ||
} | } | ||
| 2= | | 2= | ||
| Line 56: | Line 57: | ||
std::pair<const T&,const T&> minmax(const T& a, const T& b, Compare comp) | std::pair<const T&,const T&> minmax(const T& a, const T& b, Compare comp) | ||
{ | { | ||
| − | return | + | return comp(b, a) ? std::make_pair(b, a) |
| + | : std::make_pair(a, b); | ||
| + | } | ||
| + | | 3= | ||
| + | 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); | ||
| + | } | ||
| + | | 4= | ||
| + | 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=== | ===Example=== | ||
Revision as of 10:44, 24 August 2011
Template:cpp/algorithm/sidebar Template:ddcl list begin <tr class="t-dsc-header">
<td><algorithm>
<td></td> <td></td> </tr> <tr class="t-dcl ">
<td >std::pair<const T&,const T&> minmax( const T& a, const T& b );
<td > (1) </td> <td > Template:mark c++11 feature </td> </tr> <tr class="t-dcl ">
<td >std::pair<const T&,const T&> minmax( const T& a, const T& b, Compare comp );
<td > (2) </td> <td > Template:mark c++11 feature </td> </tr> <tr class="t-dcl ">
<td >std::pair<T,T> minmax( std::initializer_list ilist);
<td > (3) </td> <td > Template:mark c++11 feature </td> </tr> <tr class="t-dcl ">
<td >std::pair<T,T> minmax( std::initializer_list ilist, Compare comp );
<td > (4) </td> <td > Template:mark c++11 feature </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 Template:cpp to compare the values, the (2,4) versions use the given comparison function comp.
Contents |
Parameters
| a, b | - | the values to compare |
| ilist | - | initializer list with the values to compare |
| cmp | - | comparison function object (i.e. an object that satisfies the requirements of Compare) 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); While the signature does not need to have const&, the function must not modify the objects passed to it and must be able to accept all values of type (possibly const) |
Return value
1-2) Returns the result of Template:cpp if a<b or if a is equivalent to b. Returns the result of {cpp|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) Template:complex constant
3-4) Linear in ilist.size()
