PHP雙向隊列，雙端隊列代碼

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<?php/** * User: jifei * Date: 2013-07-30 * Time: 23:12*//** * PHP實現雙向隊列，雙端隊列 * 雙端隊列（deque，全名double-ended queue）是一種具有隊列和棧性質的資料結構。 * 雙端隊列中的元素可以從兩端彈出，插入和刪除操作限定在隊列的兩邊進行。 */class Deque{    public $queue=array();    /**     * 建構函式初始化隊列     */    public function __construct($queue=array())    {        if(is_array($queue))        {            $this->queue=$queue;        }    }    /**     * 擷取第一個元素     */    public function front()    {        return reset($this->queue);    }    /**     * 擷取最後一個元素     */    public function back()    {        return end($this->queue);    }    /**     * 判斷是否為空白     */    public function is_empty()    {       return empty($this->queue);    }    /**     * 隊列大小     */    public function size()    {       return count($this->queue);    }    /**     * 插入到尾     */    public function push_back($val)    {        array_push($this->queue,$val);    }    /**     * 插入到頭     */    public function push_front($val)    {       array_unshift($this->queue,$val);    }    /**     * 移除最後一個元素     */    public function pop_back()    {       return array_pop($this->queue);    }    /**     * 移除第一個元素     */    public function pop_front()    {        return array_shift($this->queue);    }    /**     * 清空隊列     */    public function clear()    {        $this->queue=array();    }}//初始化一個雙向隊列$deque=new Deque(array(1,2,3,4,5));echo $deque->size().PHP_EOL;echo $deque->is_empty().PHP_EOL;echo $deque->front().PHP_EOL;echo $deque->back().PHP_EOL;echo PHP_EOL;//彈出元素測試echo $deque->pop_back().PHP_EOL;echo $deque->pop_front().PHP_EOL;echo $deque->size().PHP_EOL;echo PHP_EOL;$deque->push_back(‘a‘).PHP_EOL;$deque->push_front(0).PHP_EOL;echo PHP_EOL;//插入測試echo $deque->front().PHP_EOL;echo $deque->back().PHP_EOL;echo $deque->size().PHP_EOL;echo PHP_EOL;//清空測試$deque->clear();echo $deque->is_empty();

 

PHP雙向隊列，雙端隊列代碼