The SplHeap class

Einführung

The SplHeap class provides the main functionalities of an Heap.

Klassenbeschreibung

abstract SplHeap implements Iterator , Countable {

/* Methoden */

__construct ( void )

abstract int compare ( mixed $value1 , mixed $value2 )

int count ( void )

mixed current ( void )

mixed extract ( void )

void insert ( mixed $value )

bool isEmpty ( void )

mixed key ( void )

void next ( void )

void recoverFromCorruption ( void )

void rewind ( void )

mixed top ( void )

bool valid ( void )

}

Inhaltsverzeichnis

SplHeap::compare — Compare elements in order to place them correctly in the heap while sifting up.
SplHeap::__construct — Constructs a new empty heap
SplHeap::count — Counts the number of elements in the heap.
SplHeap::current — Return current node pointed by the iterator
SplHeap::extract — Extracts a node from top of the heap and sift up.
SplHeap::insert — Inserts an element in the heap by sifting it up.
SplHeap::isEmpty — Checks whether the heap is empty.
SplHeap::key — Return current node index
SplHeap::next — Move to the next node
SplHeap::recoverFromCorruption — Recover from the corrupted state and allow further actions on the heap.
SplHeap::rewind — Rewind iterator back to the start (no-op)
SplHeap::top — Peeks at the node from the top of the heap
SplHeap::valid — Check whether the heap contains more nodes

Ein BenutzerBeitrag:
- Beiträge aktualisieren...

Michelangelo van Dam
7.10.2009 8:44


To have a good idea what you can do with SplHeap, I created a little example script that will show the rankings of Belgian soccer teams in the Jupiler League.



<?php

/**

 * A class that extends SplHeap for showing rankings in the Belgian

 * soccer tournament JupilerLeague

 */

class JupilerLeague extends SplHeap 

{

    /**

     * We modify the abstract method compare so we can sort our

     * rankings using the values of a given array

     */

    public function compare($array1, $array2)

    {

        $values1 = array_values($array1);

        $values2 = array_values($array2);

        if ($values1[0] === $values2[0]) return 0;

        return $values1[0] < $values2[0] ? -1 : 1;

    }

}



// Let's populate our heap here (data of 2009)

$heap = new JupilerLeague();

$heap->insert(array ('AA Gent' => 15));

$heap->insert(array ('Anderlecht' => 20));

$heap->insert(array ('Cercle Brugge' => 11));

$heap->insert(array ('Charleroi' => 12));

$heap->insert(array ('Club Brugge' => 21));

$heap->insert(array ('G. Beerschot' => 15));

$heap->insert(array ('Kortrijk' => 10));

$heap->insert(array ('KV Mechelen' => 18));

$heap->insert(array ('Lokeren' => 10));

$heap->insert(array ('Moeskroen' => 7));

$heap->insert(array ('Racing Genk' => 11));

$heap->insert(array ('Roeselare' => 6));

$heap->insert(array ('Standard' => 20));

$heap->insert(array ('STVV' => 17));

$heap->insert(array ('Westerlo' => 10));

$heap->insert(array ('Zulte Waregem' => 15));



// For displaying the ranking we move up to the first node

$heap->top();



// Then we iterate through each node for displaying the result

while ($heap->valid()) {

  list ($team, $score) = each ($heap->current());

  echo $team . ': ' . $score . PHP_EOL;

  $heap->next();

}

?>



This results in the following output:

Club Brugge: 21

Anderlecht: 20

Standard: 20

KV Mechelen: 18

STVV: 17

Zulte Waregem: 15

AA Gent: 15

G. Beerschot: 15

Charleroi: 12

Racing Genk: 11

Cercle Brugge: 11

Kortrijk: 10

Lokeren: 10

Westerlo: 10

Moeskroen: 7

Roeselare: 6



Hope this example paved the way for more complex implementations of SplHeap.

Ein Service von Reinhard Neidl - Webprogrammierung.

The SplHeap class

Einführung

Klassenbeschreibung

Inhaltsverzeichnis