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    SplHeap クラス

    (PHP 5 >= 5.3.0, PHP 7, PHP 8)

    はじめに

    SplHeap クラスは、ヒープの主要な機能を提供します。

    クラス概要

    abstract class SplHeap implements Iterator, Countable {
    /* メソッド */
    protected compare(mixed $value1, mixed $value2): int
    public count(): int
    public current(): mixed
    public extract(): mixed
    public insert(mixed $value): true
    public isCorrupted(): bool
    public isEmpty(): bool
    public key(): int
    public next(): void
    public recoverFromCorruption(): bool
    public rewind(): void
    public top(): mixed
    public valid(): bool
    }

    目次

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    User Contributed Notes 3 notes

    up
    66
    Michelangelo van Dam
    15 years ago
    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.
    up
    22
    igorsantos07 at gmail dot com
    10 years ago
    While Michelangelo Van Dam example (http://br2.php.net/manual/en/class.splheap.php#93930) is a great demonstration of what can be done with SplHeap, this implementation is exactly what SplPriorityQueue does - based on SplMaxHeap. If you're planning to copy that snippet, go no further! There's a SPL class that does exactly what you want :)
    up
    6
    Anthony
    8 years ago
    If you wish to build a true tree based heap, you can do so as follows (implemented with SplMinHeap, but could be SplMaxHeap if you wish for the opposite order of items):

    The stucture that we're trying to represent:

    1
    |
    +-----+--+--+-----+
    | | | |
    2 3 4 5
    | | |
    + +-+-+ +
    | | | |
    7 6 8 9
    |
    +-+-+
    | |
    10 11

    <?php
    $h     = new SplMinHeap();

    // [parent, child]
    $h->insert([9, 11]);
    $h->insert([0, 1]);
    $h->insert([1, 2]);
    $h->insert([1, 3]);
    $h->insert([1, 4]);
    $h->insert([1, 5]);
    $h->insert([3, 6]);
    $h->insert([2, 7]);
    $h->insert([3, 8]);
    $h->insert([5, 9]);
    $h->insert([9, 10]);

    for (    $h->top(); $h->valid(); $h->next()) {
    list(    $parentId, $myId) = $h->current();
    echo     "$myId ($parentId)\n";
    }
    ?>

    As you iterate over the heap, the return data will be read as if you're reading a book; ie left to right, top to bottom. It will NOT follow the relationships.

    So, the above code will output the following:

    1 (0)
    2 (1)
    3 (1)
    4 (1)
    5 (1)
    7 (2)
    6 (3)
    8 (3)
    9 (5)
    10 (9)
    11 (9)
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