std::is_sorted_until — cppreference.com

De cppreference.com

Déclaré dans l'en-tête `<algorithm>`
`template< class ForwardIt > ForwardIt is_sorted_until( ForwardIt first, ForwardIt last );`	(1)	(depuis C++11)
`template< class ForwardIt, class Compare > ForwardIt is_sorted_until( ForwardIt first, ForwardIt last, Compare comp );`	(2)	(depuis C++11)

Examine la portée et [first, last) trouve le plus grand nombre au début first dans lequel les éléments sont triés dans l'ordre croissant. La première version de la fonction utilise operator< de comparer les éléments, la seconde utilise la fonction de comparaison donnée comp .

Original:

Examines the range [first, last) and finds the largest range beginning at first in which the elements are sorted in ascending order. The first version of the function uses operator< to compare the elements, the second 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.

Paramètres

first, last	-	l'éventail des éléments à 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.
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: `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 `ForwardIterator` can be dereferenced and then implicitly converted to both of them.
Type requirements
-`ForwardIt` must meet the requirements of `ForwardIterator`.

Retourne la valeur

La limite supérieure de la gamme la plus étendue au début first dans lequel les éléments sont triés dans l'ordre croissant. Autrement dit, le it itérateur plus récente pour laquelle [first, it) plage est triée .

Original:

The upper bound of the largest range beginning at first in which the elements are sorted in ascending order. That is, the last iterator it for which range [first, it) is sorted.

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Complexité

linéaire de la distance entre first et last

Original:

linear in the distance between first and last

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Mise en œuvre possible

First version
template<class ForwardIt> ForwardIt is_sorted_until(ForwardIt first, ForwardIt last) { if (first != last) { ForwardIt next = first; while (++next != last) { if (next < first) return next; first = next; } } return last; }
Second version
template< class ForwardIt, class Compare > ForwardIt is_sorted_until(ForwardIt first, ForwardIt last, Compare comp) { if (first != last) { ForwardIt next = first; while (++next != last) { if (comp(next, first)) return next; first = next; } } return last;

First version

template<class ForwardIt>
ForwardIt is_sorted_until(ForwardIt first, ForwardIt last)
{
    if (first != last) {
        ForwardIt next = first;
        while (++next != last) {
            if (*next < *first)
                return next;
            first = next;
        }
    }
    return last;
}

Second version

template< class ForwardIt, class Compare >
ForwardIt is_sorted_until(ForwardIt first, ForwardIt last, 
                          Compare comp)
{
    if (first != last) {
        ForwardIt next = first;
        while (++next != last) {
            if (comp(*next, *first))
                return next;
            first = next;
        }
    }
    return last;

Exemple

#include <iostream>
#include <algorithm>
#include <iterator>
#include <random>

int main()
{
    std::random_device rd;
    std::mt19937 g(rd());
    const int N = 6;
    int nums[N] = {3, 1, 4, 1, 5, 9};

    const int min_sorted_size = 4;
    int sorted_size = 0;
    do {
        std::random_shuffle(nums, nums + N, g);
        int *sorted_end = std::is_sorted_until(nums, nums + N);
        sorted_size = std::distance(nums, sorted_end);

        for (auto i : nums) std::cout << i << ' ';
        std::cout << " : " << sorted_size << " initial sorted elements\n";
    } while (sorted_size < min_sorted_size);
}

Résultat possible :

4 1 9 5 1 3  : 1 initial sorted elements
4 5 9 3 1 1  : 3 initial sorted elements
9 3 1 4 5 1  : 1 initial sorted elements
1 3 5 4 1 9  : 3 initial sorted elements
5 9 1 1 3 4  : 2 initial sorted elements
4 9 1 5 1 3  : 2 initial sorted elements
1 1 4 9 5 3  : 4 initial sorted elements

Voir aussi


	vérifie si une plage est triée dans l'ordre croissant Original: checks whether a range is sorted 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 générique) [edit]