std::nth_element
De cppreference.com
 [] |
This page has been machine-translated from the English version of the wiki using Google Translate.
The translation may contain errors and awkward wording. Hover over text to see the original version. You can help to fix errors and improve the translation. For instructions click here. |
![[]](https://upload.cppreference.com/mwiki/images/3/31/Imbox_notice.png){kind=link}
<metanoindex/>
<tbody> </tbody>| Dclar dans l'en-tte <algorithm>
|
||
template< class RandomIt > void nth_element( RandomIt first, RandomIt nth, RandomIt last ); |
(1) | |
template< class RandomIt, class Compare > void nth_element( RandomIt first, RandomIt nth, RandomIt last, Compare comp ); |
(2) | |
Partiellement sortes
[first, last) la plage dans l'ordre croissant de sorte que tous les lments de la gamme sont [first, nth) moins que ceux de la gamme [nth, last). La premire version utilise operator< de comparer les lments, la deuxime version utilise la fonction de comparaison donne comp. L'lment plac dans la position nth est exactement l'lment qui se produirait dans cette position si la gamme a t entirement tri .Original:
Partially sorts the range
[first, last) in ascending order so that all elements in the range [first, nth) are less than those in the range [nth, last). The first version uses operator< to compare the elements, the second version uses the given comparison function comp. The element placed in the nth position is exactly the element that would occur in this position if the range was fully sorted.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Paramtres
| first, last | - | itrateurs d'accs alatoire dfinissant le type plage
Original: random access iterators defining the range sort The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| nth | - | itrateur accs alatoire dfinissant le point de partition genre
Original: random access iterator defining the sort partition point The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| comp | - | comparison function which returns true if the first argument is less than the second. The signature of the comparison function should be equivalent to the following:
The signature does not need to have |
| Type requirements | ||
-RandomIt must meet the requirements of ValueSwappable and RandomAccessIterator.
| ||
-The type of dereferenced RandomIt must meet the requirements of MoveAssignable and MoveConstructible.
| ||
Retourne la valeur
(Aucun)
Original:
(none)
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Complexit
Linaire dans
std::distance(first, last) en moyenne .Original:
Linear in
std::distance(first, last) on average.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Exemple
#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
int main()
{
std::vector<int> v{5, 6, 4, 3, 2, 6, 7, 9, 3};
std::nth_element(v.begin(), v.begin() + v.size()/2, v.end());
std::cout << "The median is " << v[v.size()/2] << '\n';
std::nth_element(v.begin(), v.begin()+1, v.end(), std::greater<int>());
std::cout << "The second largest element is " << v[1] << '\n';
}
Rsultat :
The median is 5
The second largest element is 7
Voir aussi
copies et partiellement Trie une plage d'lments Original: copies and partially sorts a range of elements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction gnrique) | |
Trie une plage d'lments, tout en prservant l'ordre entre des lments gaux Original: sorts a range of elements while preserving order between equal elements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction gnrique) | |
trie une plage dans l'ordre ascendant Original: sorts a range into ascending order The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction gnrique) | |