PHP - PriorityQueue Functions

Quiz

PriorityQueue is very similar to the Queue. The values are pushed into the queue with an assigned priority, and the value with the highest priority can always be at the front of the queue. It is implemented by using a max heap.

Requirements

PHP 7 is required for both extension and the compatibility polyfill.

Installation

The easiest way to install data structure by using the PECL extension.

pecl install ds

Syntax

public Ds\PriorityQueue::functionName()

Class Synopsis

Ds\PriorityQueue implements Ds\Collection {
   /* Constants */
   const int MIN_CAPACITY = 8 ;
   
   /* Methods */
   public void allocate( int $capacity )
   public int capacity( void )
   public void clear( void )
   public Ds\PriorityQueue copy( void )
   public bool isEmpty( void )
   public mixed peek( void )
   public mixed pop( void )
   public void push( mixed $value, int $priority )
   public array toArray( void )
}

Predefined Constants

Ds\PriorityQueue::MIN_CAPACITY

List of Functions

Here is the complete list of functions available in the PriorityQueue class −

Sr.No	Function & Description	PHP Version
1	Ds\PriorityQueue::allocate() Function This function can allocate enough memory for the required capacity.
2	Ds\PriorityQueue::capacity() Function This function can return the current capacity.
3	Ds\PriorityQueue::clear() Function This function can remove all values from the queue.
4	Ds\PriorityQueue::__construct() Function This function can create a new instance.
5	Ds\PriorityQueue::copy() Function This function can return a shallow copy of the queue.
6	Ds\PriorityQueue::count() Function This function can be used to get the count of elements present in PriorityQueue.
7	Ds\PriorityQueue::isEmpty() Function This function can return whether the queue is empty.
8	Ds\PriorityQueue::jsonSerialize() Function This function can return a representation that can be converted to JSON.
9	Ds\PriorityQueue::peek() Function This function can return a value at the front of a queue.
10	Ds\PriorityQueue::pop() Function This function can remove and return a value with highest priority.
11	Ds\PriorityQueue::push() Function This function can push the values with a given priority into a queue.
12	Ds\PriorityQueue::toArray() Function This function can convert the queue to an array.

Important Note

Here is the important point to keep in mind −

The "first in, first out" ordering is preserved for values with the same priority.
Iterating over a PriorityQueue destructively is equivalent to continuously running pop operations across the queue until it is empty.

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