priority-heap-queue

Priority queue implemented using a heap

npm install priority-heap-queue
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priority-heap-queue

Stability: 1 - Experimental

Priority queue.

Installation

npm install priority-heap-queue

Tests

npm test

Usage

var PriorityQueue = require('priority-heap-queue');

var maxQueue = new PriorityQueue();
var minQueue = new PriorityQueue({kind: 'min'});

Overview

TODO

Documentation

PriorityQueue

A JavaScript implementation of a priority queue using heap data structure.

WARNING: This implementation uses 1-indexed arrays (instead of 0-indexed) arrays.

PriorityQueue.heapDecreaseKey(array, index, value)

  • array: Array 1-indexed array storing the heap structure
  • index: Integer index of the key to decrease
  • value: Integer the value to decrease the key to

Sets the value of the key at index to value and ensures heap property is maintained as a result.

PriorityQueue.heapIncreaseKey(array, index, value)

  • array: Array 1-indexed array storing the heap structure
  • index: Integer index of the key to increase
  • value: Integer the value to increase the key to

Sets the value of the key at index to value and ensures heap property is maintained as a result.

PriorityQueue.maxHeapify(array, index, heapSize)

  • array: Array 1-indexed array storing the heap structure
  • index: Integer the array index to start maxHeapify procedure on
  • heapSize: Integer heap size

Ensures that the max-heap property is satisfied for the sub-tree rooted at index of the array representing a binary tree.

PriorityQueeu.minHeapify(array, index, heapSize)

  • array: Array 1-indexed array storing the heap structure
  • index: Integer the array index to start maxHeapify procedure on
  • heapSize: Integer heap size

Ensures that the min-heap property is satisfied for the sub-tree rooted at index of the array representing a binary tree.

new PriorityQueue(options)

  • options:
    • kind: String One of min, max (default: max)

Creates a new PriorityQueue.

priorityQueue.decreaseKey(index, value)

  • index: Integer index of the key to decrease
  • value: Integer the value to decrease the key to

Sets the value of the key at index to value and ensures heap property is maintained as a result.

priorityQueue.extractMax()

Removes and returns the element with the largest key.

priorityQueue.extractMin()

Removes and returns the element with the smallest key.

priorityQueue.increaseKey(index, value)

  • index: Integer index of the key to increase
  • value: Integer the value to increase the key to

Sets the value of the key at index to value and ensures heap property is maintained as a result.

priorityQueue.insert(key, element)

  • key: Integer key of the element to be inserted
  • element: Any element to associate with the key

Inserts the element into the priority queue at the specified key.

priorityQueue.maximum()

Returns the element with the largest key. The element is not removed.

priorityQueue.minimum()

Returns the element with the smallest key. The element is not removed.

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