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Using the SimplePriorityQueue

BlueRaja edited this page Nov 8, 2016 · 8 revisions

SimplePriorityQueue is built to work exactly as you'd expect, without all the gotchas that FastPriorityQueue has. It's stable, thread-safe, auto-resizes itself, performs safety checks, etc.

Here is the IPriorityQueue interface, with all the documentation comments removed:

public interface IPriorityQueue<TItem, TPriority> : IEnumerable<TItem>
{
	void Enqueue(TItem node, TPriority priority);
	TItem Dequeue();
	void Clear();
	bool Contains(TItem node);
	void Remove(TItem node);
	void UpdatePriority(TItem node, TPriority priority);
	TItem First { get; }
	int Count { get; }
}

Each method works exactly as you'd expect. For more information about each method, see the method documentation.

Example

Here is a fully working minimal example

using System;
using Priority_Queue;

namespace Priority_Queue_Example
{
    public static class SimplePriorityQueueExample
    {
        public static void RunExample()
        {
            //First, we create the priority queue.
            //By default, priority-values are of type 'float'
            SimplePriorityQueue<string> priorityQueue = new SimplePriorityQueue<string>();

            //Now, let's add them all to the queue (in some arbitrary order)!
            priorityQueue.Enqueue("4 - Joseph", 4);
            priorityQueue.Enqueue("2 - Tyler", 0); //Note: Priority = 0 right now!
            priorityQueue.Enqueue("1 - Jason", 1);
            priorityQueue.Enqueue("4 - Ryan", 4);
            priorityQueue.Enqueue("3 - Valerie", 3);

            //Change one of the string's priority to 2.  Since this string is already in the priority queue, we call UpdatePriority() to do this
            priorityQueue.UpdatePriority("2 - Tyler", 2);

            //Finally, we'll dequeue all the strings and print them out
            while(priorityQueue.Count != 0)
            {
                string nextUser = priorityQueue.Dequeue();
                Console.WriteLine(nextUser);
            }

            //Output:
            //1 - Jason
            //2 - Tyler
            //3 - Valerie
            //4 - Joseph
            //4 - Ryan

            //Notice that when two strings with the same priority were enqueued, they were dequeued in the same order that they were enqueued.
        }
    }
}
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