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The SplHeap class

(PHP 5 >= 5.3.0)

简介

The SplHeap class provides the main functionalities of a Heap.

类摘要

abstract SplHeap implements Iterator , Countable {
/* 方法 */
__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 )
}

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PHP手册 - N: The SplHeap class

用户评论:

Michelangelo van Dam (07-Oct-2009 07:44)

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.