std::binary_search
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<tbody> </tbody>| Dclar dans l'en-tte <algorithm>
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template< class ForwardIt, class T > bool binary_search( ForwardIt first, ForwardIt last, const T& value ); |
(1) | |
template< class ForwardIt, class T, class Compare > bool binary_search( ForwardIt first, ForwardIt last, const T& value, Compare comp ); |
(2) | |
Vrifie si le
[first, last) gamme trie contient un lment gal value. La premire version utilise operator< de comparer les lments, la deuxime version utilise la fonction de comparaison donne comp .Original:
Checks if the sorted range
[first, last) contains an element equal to value. The first version uses operator< to compare the elements, the second version uses the given comparison function comp.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 | - | l'ventail des lments examiner
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. |
| value | - | valeur comparer les lments d'
Original: value to compare the elements to 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 | ||
-ForwardIt must meet the requirements of ForwardIterator.
| ||
Retourne la valeur
true si un lment gal value se trouve, false autrement .Original:
true if an element equal to value is found, false otherwise.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
Logarithmique de la distance entre
first et lastOriginal:
Logarithmic in the distance between
first and lastThe 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.
Mise en uvre possible
| First version |
|---|
template<class ForwardIt, class T>
bool binary_search(ForwardIt first, ForwardIt last, const T& value)
{
first = std::lower_bound(first, last, value);
return (first != last && !(value < *first));
}
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| Second version |
template<class ForwardIt, class T, class Compare>
bool binary_search(ForwardIt first, ForwardIt last, const T& value, Compare comp)
{
first = std::lower_bound(first, last, value);
return (first != last && !(comp(value, *first));
}
|
Exemple
#include <iostream>
#include <algorithm>
#include <vector>
int main()
{
std::vector<int> haystack {1, 3, 4, 5, 9};
std::vector<int> needles {1, 2, 3};
for (auto needle : needles) {
std::cout << "Searching for " << needle << '\n';
if (std::binary_search(haystack.begin(), haystack.end(), needle)) {
std::cout << "Found " << needle << '\n';
} else {
std::cout << "no dice!\n";
}
}
}
Rsultat :
Searching for 1
Found 1
Searching for 2
no dice!
Searching for 3
Found 3
Voir aussi
rendements varient d'lments correspondant une cl spcifique Original: returns range of elements matching a specific key The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction gnrique) | |