PHP bidirectional queue, double-ended queue code

/** * User:jifei * date:2013-07-30 * Time:23:12 */ /** * PHP implementation of two-way queue, double-ended queue * Double-ended queue (deque, full name double-ended queue) is a data structure with queue and stack properties. * Elements in a double-ended queue can be ejected from both ends, and insert and delete operations are scoped to both sides of the queue. */ Class Deque { Public $queue =array (); /** * Constructor Initialization queue */ Public function __construct ($queue =array ()) { if (Is_array ($queue)) { $this->queue= $queue; } } /** * Get the first element */ Public Function Front () { Return Reset ($this->queue); } /** * Get last Element */ Public Function back () { Return End ($this->queue); } /** * Determine if it is empty */ Public Function Is_empty () { return empty ($this->queue); } /** * Queue Size */ Public Function size () { Return count ($this->queue); } /** * Insert to Tail */ Public Function push_back ($val) { Array_push ($this->queue, $val); } /** * Insert to Head */ Public Function Push_front ($val) { Array_unshift ($this->queue, $val); } /** * Remove the last element */ Public Function Pop_back () { Return Array_pop ($this->queue); } /** * Remove the first element */ Public Function Pop_front () { Return Array_shift ($this->queue); } /** * Empty Queue */ Public Function Clear () { $this->queue=array (); } } Initialize a two-way queue $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; Pop-up element test 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; Insert Test echo $deque->front (). Php_eol; echo $deque->back (). Php_eol; echo $deque->size (). Php_eol; Echo Php_eol; Empty test $deque->clear (); echo $deque->is_empty (); Copy Code

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