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php原生实现队列

2026-02-15 18:17:48PHP

PHP原生实现队列的方法

在PHP中，队列可以通过数组或链表等数据结构原生实现。以下是几种常见的实现方式：

使用数组实现队列

PHP的数组函数可以方便地实现队列的先进先出（FIFO）特性。以下是使用数组实现队列的示例代码：

$queue = [];

// 入队操作
array_push($queue, 'item1');
array_push($queue, 'item2');

// 出队操作
$item = array_shift($queue);
echo $item; // 输出 'item1'

使用SplQueue类

PHP的SPL（Standard PHP Library）提供了SplQueue类，专门用于实现队列功能：

$queue = new SplQueue();

// 入队操作
$queue->enqueue('item1');
$queue->enqueue('item2');

// 出队操作
$item = $queue->dequeue();
echo $item; // 输出 'item1'

链表实现队列

如果需要更底层地实现队列，可以使用链表结构：

class Node {
    public $data;
    public $next;

    public function __construct($data) {
        $this->data = $data;
        $this->next = null;
    }
}

class Queue {
    private $front;
    private $rear;

    public function __construct() {
        $this->front = $this->rear = null;
    }

    public function enqueue($data) {
        $newNode = new Node($data);

        if ($this->rear == null) {
            $this->front = $this->rear = $newNode;
            return;
        }

        $this->rear->next = $newNode;
        $this->rear = $newNode;
    }

    public function dequeue() {
        if ($this->front == null) {
            return null;
        }

        $temp = $this->front;
        $this->front = $this->front->next;

        if ($this->front == null) {
            $this->rear = null;
        }

        return $temp->data;
    }
}

// 使用示例
$q = new Queue();
$q->enqueue(10);
$q->enqueue(20);
echo $q->dequeue(); // 输出 10

环形队列实现

对于需要固定大小的队列，可以实现环形队列：

class CircularQueue {
    private $queue;
    private $size;
    private $front;
    private $rear;

    public function __construct($size) {
        $this->size = $size;
        $this->queue = array_fill(0, $size, null);
        $this->front = $this->rear = -1;
    }

    public function enqueue($data) {
        if (($this->rear + 1) % $this->size == $this->front) {
            throw new Exception("Queue is full");
        }

        if ($this->front == -1) {
            $this->front = $this->rear = 0;
        } else {
            $this->rear = ($this->rear + 1) % $this->size;
        }

        $this->queue[$this->rear] = $data;
    }

    public function dequeue() {
        if ($this->front == -1) {
            throw new Exception("Queue is empty");
        }

        $data = $this->queue[$this->front];

        if ($this->front == $this->rear) {
            $this->front = $this->rear = -1;
        } else {
            $this->front = ($this->front + 1) % $this->size;
        }

        return $data;
    }
}

优先级队列实现

对于需要按优先级处理的队列，可以实现优先级队列：

php原生实现队列

class PriorityQueue {
    private $queue;

    public function __construct() {
        $this->queue = [];
    }

    public function enqueue($item, $priority) {
        $this->queue[] = [
            'item' => $item,
            'priority' => $priority
        ];

        usort($this->queue, function($a, $b) {
            return $a['priority'] - $b['priority'];
        });
    }

    public function dequeue() {
        if (empty($this->queue)) {
            return null;
        }

        $item = array_shift($this->queue);
        return $item['item'];
    }
}