PHP 8.5.0 Alpha 2 available for testing

The SplMinHeap class

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

简介

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

类摘要

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

目录

  • SplMinHeap::compare — Compare elements in order to place them correctly in the heap while sifting up
添加备注

用户贡献的备注 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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