PHP bidirectional queue implementation code

PHP bidirectional queue implementation code

1. what is a bidirectional queue? Deque, full name double-ended queue, is a data structure with queue and stack properties. Elements in a dual-end queue can pop up from both ends, and the limited insert and delete operations are performed at both ends of the table. A two-way queue (dual-end queue) is like a queue, but elements can be added or removed at any end. Reference: http://zh.wikipedia.org/zh-cn/%E5%8F%8C%E7% AB %AF%E9%98%9F%E5%88%97 2. php implements two-way queue code Class DoubleQueue { Public $ queue = array (); /** (Tail) team up **/ Public function addLast ($ value) { Return array_push ($ this-> queue, $ value ); } /** (Tail) team-OUT **/ Public function removeLast () { Return array_pop ($ this-> queue ); } /** (Header) team up **/ Public function addFirst ($ value) { Return array_unshift ($ this-> queue, $ value ); } /** (Head) team-OUT **/ Public function removeFirst () { Return array_shift ($ this-> queue ); } /** Clear the queue **/ Public function makeEmpty () { Unset ($ this-> queue ); } /** Get the column header **/ Public function getFirst () { Return reset ($ this-> queue ); } /** Get the end of a column **/ Public function getLast () { Return end ($ this-> queue ); } /** Get length **/ Public function getLength () { Return count ($ this-> queue ); } }