std::lexicographical_compare

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Algoritmo libreria

Funzioni Original: Functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Non modifica le operazioni di sequenza Original: Non-modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
all_of any_of none_of (C++11) (C++11) (C++11) for_each count count_if mismatch equal	find find_if find_if_not (C++11) find_end find_first_of adjacent_find search search_n
Modifica delle operazioni di sequenza Original: Modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
copy copy_if (C++11) copy_n (C++11) copy_backward move (C++11) move_backward (C++11) fill fill_n transform generate generate_n remove remove_if remove_copy remove_copy_if	replace replace_if replace_copy replace_copy_if swap swap_ranges iter_swap reverse reverse_copy rotate rotate_copy random_shuffle shuffle   (C++11) unique unique_copy
Partizionamento operazioni Original: Partitioning operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_partitioned (C++11) partition partition_copy (C++11)	stable_partition partition_point (C++11)
Ordinamento delle operazioni (su intervalli ordinati) Original: Sorting operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_sorted (C++11) is_sorted_until (C++11) sort	partial_sort partial_sort_copy stable_sort nth_element
Binarie (le operazioni di ricerca sui campi ordinati) Original: Binary search operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
lower_bound upper_bound	binary_search equal_range
Impostare le operazioni (su intervalli ordinati) Original: Set operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
merge inplace_merge includes	set_difference set_intersection set_symmetric_difference set_union
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is_heap is_heap_until (C++11) make_heap	push_heap pop_heap sort_heap
Minimo / massimo le operazioni Original: Minimum/maximum operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
max max_element min min_element minmax (C++11) minmax_element (C++11)	lexicographical_compare is_permutation (C++11) next_permutation prev_permutation
Operazioni numeriche Original: Numeric operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
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qsort	bsearch

 

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Elemento definito nell'header <algorithm>
template< class InputIt1, class InputIt2 > bool lexicographical_compare( InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2 );	(1)
template< class InputIt1, class InputIt2, class Compare > bool lexicographical_compare( InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2, Compare comp );	(2)

Controlla se il primo intervallo è [first1, last1) lexicographically' inferiore al [first2, last2) secondo intervallo. La prima versione utilizza operator< di confrontare gli elementi, la seconda versione utilizza la funzione di confronto dato comp.

Original:

Checks if the first range [first1, last1) is lexicographically less than the second range [first2, last2). The first version uses operator< to compare the elements, the second version uses the given comparison function comp.

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Confronto lessicografico è un'operazione con le seguenti proprietà:

Original:

Lexicographical comparison is a operation with the following properties:

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• Due campi sono confrontati elemento per elemento.

  Original:

  Two ranges are compared element by element.

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• L'elemento mismatching prima definisce quale intervallo è lexicographically meno o' superiore rispetto agli altri.

  Original:

  The first mismatching element defines which range is lexicographically less or greater than the other.

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• Se un intervallo è un prefisso di un altro, la gamma più breve è lexicographically' di meno rispetto agli altri.

  Original:

  If one range is a prefix of another, the shorter range is lexicographically less than the other.

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• Se due serie hanno elementi equivalenti e sono della stessa lunghezza, gli intervalli sono uguali lessicograficamente'.

  Original:

  If two ranges have equivalent elements and are of the same length, then the ranges are lexicographically equal.

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• Un campo a vuoto è lexicographically' meno di qualsiasi non vuota gamma.

  Original:

  An empty range is lexicographically less than any non-empty range.

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• Due campi sono vuoti lessicografico' uguali.

  Original:

  Two empty ranges are lexicographically equal.

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Parametri

first1, last1	-	la prima gamma di elementi da esaminare Original: the first 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.
first2, last2	-	il secondo intervallo di elementi da esaminare Original: the second 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 objects of types InputIt1 and InputIt2 can be dereferenced and then implicitly converted to Type1 and Type2 respectively. ​
Type requirements
- InputIt1, InputIt2 must meet the requirements of InputIterator.

Valore di ritorno

true se il primo intervallo è lexicographically meno della seconda.

Original:

true if the first range is lexicographically less than the second.

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Complessità

Alla maggior parte delle applicazioni di 2·min(N1, N2) l'operazione di confronto, dove N1 = std::distance(first1, last1) e N2 = std::distance(first2, last2).

Original:

At most 2·min(N1, N2) applications of the comparison operation, where N1 = std::distance(first1, last1) and N2 = std::distance(first2, last2).

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Possibile implementazione

First version
template<class InputIt1, class InputIt2> bool lexicographical_compare(InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2) { for ( ; (first1 != last1) && (first2 != last2); first1++, first2++ ) { if (*first1 < *first2) return true; if (*first2 < *first1) return false; } return (first1 == last1) && (first2 != last2); }
Second version
template<class InputIt1, class InputIt2, class Compare> bool lexicographical_compare(InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2, Compare comp) { for ( ; (first1 != last1) && (first2 != last2); first1++, first2++ ) { if (comp(*first1, *first2)) return true; if (comp(*first2, *first1)) return false; } return (first1 == last1) && (first2 != last2); }

Esempio

#include <algorithm>
#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>

int main()
{
    std::vector<char> v1 {'a', 'b', 'c', 'd'};
    std::vector<char> v2 {'a', 'b', 'c', 'd'};

    std::srand(std::time(0));
    while (!std::lexicographical_compare(v1.begin(), v1.end(),
                                         v2.begin(), v2.end())) {
        for (auto c : v1) std::cout << c << ' ';
        std::cout << ">= ";
        for (auto c : v2) std::cout << c << ' ';
        std::cout << '\n';

        std::random_shuffle(v1.begin(), v1.end());
        std::random_shuffle(v2.begin(), v2.end());
    }

    for (auto c : v1) std::cout << c << ' ';
    std::cout << "< ";
    for (auto c : v2) std::cout << c << ' ';
    std::cout << '\n';
}

Possible output:

a b c d >= a b c d 
d a b c >= c b d a 
b d a c >= a d c b 
a c d b < c d a b