PHP 8.5.0 Alpha 2 available for testing

The SplMinHeap class

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

Introduzione

The SplMinHeap class provides the main functionalities of a heap, keeping the minimum on the top.

Sommario della classe

class SplMinHeap extends SplHeap {
/* Metodi */
protected compare(mixed $value1, mixed $value2): int
/* Metodi ereditati */
protected SplHeap::compare(mixed $value1, mixed $value2): int
public SplHeap::insert(mixed $value): true
public SplHeap::key(): int
}

Indice dei contenuti

  • SplMinHeap::compare — Compare elements in order to place them correctly in the heap while sifting up
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User Contributed Notes 2 notes

up
3
gom
5 years ago
I experimented what happens when arrays are inserted:

<?php
$heap
= new SplMinHeap();
$heap->insert([22,333]);
$heap->insert([2,33]);
$heap->insert([222,3]);

var_export($heap->extract());
echo
'<br>';
var_export($heap->extract());
echo
'<br>';
var_export($heap->extract());
?>

Output:

array ( 0 => 2, 1 => 33, )
array ( 0 => 22, 1 => 333, )
array ( 0 => 222, 1 => 3, )
up
0
andy at nospam dot airslash dot net
10 days ago
To expand on gom's comment, SplMinHeap will also take into account the subsequent elements of the array you inserted, if the elements before that are equal.

<?php
$heap
= new SplMinHeap();
$heap->insert([0, 10]);
$heap->insert([0, 30]);
$heap->insert([0, 15]);
while (!
$heap->isEmpty()) {
[
$a, $b] = $heap->extract();
echo
"a:$a, b:$b\n";
}
echo
"---\n";
$heap->insert([0, 10, 100]);
$heap->insert([0, 10, 300]);
$heap->insert([0, 10, 150]);
while (!
$heap->isEmpty()) {
[
$a, $b, $c] = $heap->extract();
echo
"a:$a, b:$b, c:$c\n";
}
?>

will output:

a:0, b:10
a:0, b:15
a:0, b:30
---
a:0, b:10, c:100
a:0, b:10, c:150
a:0, b:10, c:300
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