std::pop_heap - cppreference.com

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Elemento definito nell'header `<algorithm>`

`template< class RandomIt > void pop_heap( RandomIt first, RandomIt last );`	(1)

`template< class RandomIt, class Compare > void pop_heap( RandomIt first, RandomIt last, Compare comp );`	(2)

Swap il valore nella first posizione e il valore nella last-1 posizione e rende il [first, last-1) sottointervallo in un' heap. Questo ha l'effetto di eliminare la prima (più grande) elemento dall'heap definito dal [first, last) gamma.

Original:

Swaps the value in the position first and the value in the position last-1 and makes the subrange [first, last-1) into a heap. This has the effect of removing the first (largest) element from the heap defined by the range [first, last).

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La prima versione della funzione utilizza operator< per confrontare gli elementi, il secondo utilizza la funzione di confronto dato comp.

Original:

The first version of the function uses operator< to compare the elements, the second uses the given comparison function comp.

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Parametri

first, last	-	la gamma di elementi che definiscono l'heap valido non vuoto da modificare Original: the range of elements defining the valid nonempty heap to modify 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 `RandomIt` can be dereferenced and then implicitly converted to both of them.
Type requirements
-`RandomIt` must meet the requirements of `ValueSwappable` and `RandomAccessIterator`.
-The type of dereferenced `RandomIt` must meet the requirements of `MoveAssignable` and `MoveConstructible`.

Valore di ritorno

(Nessuno)

Original:

(none)

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Complessità

Al massimo 2 × log (N) confronti N=std::distance(first, last) dove.

Original:

At most 2×log(N) comparisons where N=std::distance(first, last).

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Note

Un mucchio' è una serie di elementi [f,l) che ha le seguenti proprietà:

Original:

A heap is a range of elements [f,l) that has the following properties:

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*f è l'elemento più grande della gamma
Original:
*f is the largest element in the range
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un nuovo elemento può essere aggiunto utilizzando std::push_heap()
Original:
a new element can be added using std::push_heap()
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il primo elemento può essere rimosso utilizzando std::pop_heap()
Original:
the first element can be removed using std::pop_heap()
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L'effettiva disposizione degli elementi è definita attuazione.

Original:

The actual arrangement of the elements is implementation defined.

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Esempio

#include <iostream>
#include <algorithm>

int main()
{
    std::vector<int> v { 3, 1, 4, 1, 5, 9 };

    std::make_heap(v.begin(), v.end());

    std::cout << "v: ";
    for (auto i : v) std::cout << i << ' ';
    std::cout << '\n';

    std::pop_heap(v.begin(), v.end()); // moves the largest to the end

    std::cout << "after pop_heap: ";
    for (auto i : v) std::cout << i << ' ';
    std::cout << '\n';

    int largest = v.back();
    v.pop_back();  // actually removes the largest element
    std::cout << "largest element: " << largest << '\n';

    std::cout << "heap without largest: ";
    for (auto i : v) std::cout << i << ' ';
    std::cout << '\n';
}

Output:

v: 9 5 4 1 1 3 
after pop_heap: 5 3 4 1 1 9 
largest element: 9
heap without largest: 5 3 4 1 1

Vedi anche


	aggiunge un elemento a un heap Original: adds an element to a heap The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (funzione di modello) [modifica]