https://github.com/mikolalysenko/functional-priority-queue

A functional priority queue in JavaScript
https://github.com/mikolalysenko/functional-priority-queue

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A functional priority queue in JavaScript

• Host: GitHub
• URL: https://github.com/mikolalysenko/functional-priority-queue
• Owner: mikolalysenko
• License: mit
• Created: 2015-04-09T14:28:56.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2015-04-09T14:34:04.000Z (over 9 years ago)
• Last Synced: 2024-10-20T14:26:15.522Z (2 months ago)
• Language: JavaScript
• Size: 117 KB
• Stars: 20
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
functional-priority-queue

=========================

A [confluently](http://en.wikipedia.org/wiki/Persistent_data_structure#Confluently_persistent) [persistent](http://en.wikipedia.org/wiki/Persistent_data_structure) [functional](http://en.wikipedia.org/wiki/Purely_functional) [priority queue](http://en.wikipedia.org/wiki/Priority_queue).  

#### Technical details

This priority queue is implemented using a [pairing heap](http://en.wikipedia.org/wiki/Pairing_heap), though because it uses a pure functional interface it does not support the decrease-key function (as locating a node within the heap without maintaining cyclic pointers is expensive).

# Example

```javascript

var fpq = require('functional-priority-queue')

```

# Installation

This module works in any node-flavored CommonJS environment, including [node.js](https://nodejs.org/), [iojs](https://iojs.org/en/index.html) and [browserify](http://browserify.org/).  You can install it using the [npm package manager](https://docs.npmjs.com/) with the following command:

```

npm i functional-priority-queue

```

# API

```javascript

var fpq = require('functional-priority-queue')

```

#### `var pq = fpq(keys, values)`

Creates a new functional priority queue

* `keys` is an array of weights which are used to order the elements in the priority queue

* `values` is an array of values which are ascoiated to the keys

**Returns** A new priority queue

**Time Complexity** `O(keys.length)`

#### `pq.minKey`

The key of the smallest element in the priority queue

#### `pq.minValue`

The value of the smallest element in the priority queue

#### `var next = fpq.push(pq, key, value)`

Adds an item to the priority queue

* `pq` is the priority queue into which we are inserting

* `key` is the key we are inserting into the priority queue

* `value` is the value we are inserting into the priority queue

**Returns** A new priority queue with the pair `(key, value)` added to it

**Time Complexity** `O(1)`

#### `var next = fpq.pop(pq)`

Removes the top element from a priority queue

* `pq` is a priority queue which we are removing from

**Returns** A copy of `pq` with the minimal element deleted

**Time Complexity** `O(log(n))` [*amortized*](http://en.wikipedia.org/wiki/Amortized_analysis)

#### `var next = fpq.merge(pq1, pq2, ...pqn)`

Merges a list of priority queues into a single priority queue

* `pq1, pq2, ...pqn` is a list of `n` priority queues

**Returns** A single priority queue whose contents are equal to all the input priority queues combined

**Time Complexity** `O(n)`

# License

(c) 2015 Mikola Lysenko. MIT License