PHP 数据结构深度解析

PHP 8 拥有高效的底层数组（Zend HashTable）与标准 SPL 数据结构扩展：

• 统一数组（Array）：结合有序映射与动态数组的混合 HashTable。
• SPL 专用容器：SplDoublyLinkedList、SplPriorityQueue、SplFixedArray 提供专有数据结构的高性能原生支持。

---

📊 核心容器特征

结构	PHP 实现	典型复杂度	特性
数组	array (HashTable)	增删查 $O(1)$	默认通用有序键值结构
双向链表	SplDoublyLinkedList	两端操作 $O(1)$	栈与双端队列结构
优先队列	SplPriorityQueue	入队出队 $O(\log n)$	基于堆的优先级调度

---

1. 线性结构：PHP 数组与 SplDoublyLinkedList

<?php
echo "=== PHP Dynamic Arrays & SplDoublyLinkedList ===\n";
$arr = [10, 20];
$arr[] = 30;
assert(count($arr) === 3);
assert($arr[1] === 20);

$dll = new SplDoublyLinkedList();
$dll->push("tail");
$dll->unshift("head");
assert($dll->bottom() === "head");
assert($dll->top() === "tail");

echo "PHP Array count: " . count($arr) . ", DLL count: " . $dll->count() . "\n";
echo "PHP Dynamic Array tests passed successfully.\n";

🐳 Docker Verified📋php:8.3-alpine

Exit Code: 0

=== PHP Dynamic Arrays & SplDoublyLinkedList ===
PHP Array count: 3, DLL count: 2
PHP Dynamic Array tests passed successfully.

---

2. 堆与优先队列：SplPriorityQueue

<?php
echo "=== PHP SplPriorityQueue (Max Heap) ===\n";
$pq = new SplPriorityQueue();
$pq->insert("Task Low", 10);
$pq->insert("Task High", 50);
$pq->insert("Task Mid", 30);

assert($pq->top() === "Task High");
assert($pq->extract() === "Task High");
assert($pq->extract() === "Task Mid");
assert($pq->extract() === "Task Low");

echo "PHP SplPriorityQueue tests passed successfully.\n";

🐳 Docker Verified📋php:8.3-alpine

Exit Code: 0

=== PHP SplPriorityQueue (Max Heap) ===
PHP SplPriorityQueue tests passed successfully.