Espacios de nombres
Variantes
Acciones

std::lexicographical_compare

De cppreference.com
< cpp‎ | algorithm

 
 
Biblioteca de algoritmos
Políticas de ejecución (C++17)
Operaciones no modificadoras de secuencia
(C++11)(C++11)(C++11)
(C++17)
lexicographical_compare

Operaciones modificadoras de secuencia
Operaciones en almacenamiento no inicializado
Operaciones de partición
Operaciones de ordenación
(C++11)
Operaciones de búsqueda binaria
Operaciones de set (en rangos ordenados)
Operaciones de pila
(C++11)
Operaciones minimo/maximo
(C++11)
(C++17)
Permutaciones
Operaciones numéricas
Bibliotecas C
 
Definido en la cabecera <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)
Comprueba si el primer intervalo es [first1, last1) lexicográfico' menor que el [first2, last2) segundo rango. La primera versión utiliza operator< para comparar los elementos, la segunda versión utiliza la función de comparación dado 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.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Comparación lexicográfica es una operación con las siguientes propiedades:
Original:
Lexicographical comparison is a operation with the following properties:
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
  • Dos cadenas se comparan elemento por elemento .
    Original:
    Two ranges are compared element by element.
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
  • El elemento descalce primera define qué rango es menos lexicográfico''' o mayor que el otro .
    Original:
    The first mismatching element defines which range is lexicographically less or greater than the other.
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
  • Si una serie es un prefijo de otro, el rango más corto es lexicográfico' menos que el otro .
    Original:
    If one range is a prefix of another, the shorter range is lexicographically less than the other.
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
  • Si dos gamas tienen elementos equivalentes y son de la misma longitud, entonces los rangos son iguales lexicográficamente' .
    Original:
    If two ranges have equivalent elements and are of the same length, then the ranges are lexicographically equal.
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
  • Un rango de vacío es lexicográfico' menos de cualquier rango que no esté vacía .
    Original:
    An empty range is lexicographically less than any non-empty range.
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
  • Dos cadenas vacías son lexicográfico' igual .
    Original:
    Two empty ranges are lexicographically equal.
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.

Contenido

[editar] Parámetros

first1, last1 -
la primera gama de elementos a examinar
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 -
la segunda gama de elementos a examinar
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. ​

Requerimientos de tipo
-
InputIt1, InputIt2 debe reunir los requerimientos de InputIterator.

[editar] Valor de retorno

true si el primer intervalo es lexicográficamente' menos que el segundo .
Original:
true if the first range is lexicographically less than the second.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

[editar] Complejidad

En la mayoría de aplicaciones 2·min(N1, N2) de la operación de comparación, donde N1 = std::distance(first1, last1) y 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).
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

[editar] Posible implementación

Primera versión
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);
}
Segunda versión
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);
}

[editar] Ejemplo

#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';
}

Posible salida:

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