What does php two-way queue mean?

php Bidirectional queue refers to a data structure with the properties of queue and stack; elements in the bidirectional queue can be popped from both ends, and it limits insertion and deletion operations to be performed at both ends of the table; bidirectional queue Like a queue, but you can add or remove elements at either end.

The operating environment of this article: Windows 7 system, PHP version 7.1, DELL G3 computer

What does php bidirectional queue mean?

PHP - Use PHP to implement a two-way queue

1. Introduction

deque, the full name is double-ended queue, is a A data structure that has properties of queues and stacks. Elements in a double-ended queue can be popped from both ends, and insertion and deletion operations are limited to both ends of the table. A deque (double-ended queue) is like a queue, but you can add or remove elements from either end.

Reference: http://zh.wikipedia.org/zh-cn/Double-Ended Queue

2.PHP implementation code

<?php
class DoubleQueue  
{ 
    public $queue = array(); 
    
    /**（尾部）入队  **/ 
    public function addLast($value)  
    { 
        return array_push($this->queue,$value); 
    } 
    /**（尾部）出队**/ 
    public function removeLast()  
    { 
        return array_pop($this->queue); 
    } 
    /**（头部）入队**/ 
    public function addFirst($value)  
    { 
        return array_unshift($this->queue,$value); 
    } 
    /**（头部）出队**/ 
    public function removeFirst()  
    { 
        return array_shift($this->queue); 
    } 
    /**清空队列**/ 
    public function makeEmpty()  
    { 
        unset($this->queue);
    } 
    
    /**获取列头**/
    public function getFirst()  
    { 
        return reset($this->queue); 
    } 
    /** 获取列尾 **/
    public function getLast()  
    { 
        return end($this->queue); 
    }
    /** 获取长度 **/
    public function getLength()  
    { 
        return count($this->queue); 
    }
    
}

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