score-heap

ScoreHeap

A heap optimized for frequent updates. Maintains a sorted list with partitions so only items within a modified partition need to be reindexed. Returns the highest score (int32) in the heap, else null if the heap is empty.

Working Example

import ScoreHeap from 'score-heap';

let objs = [];
let scores = [];

// make a million entries with score = array index
for (let i = 0; i < 1000000; ++i) {

	// this is the source array, the entries can be anything
	objs.push({ i });

	// initial scores will be passed into the new ScoreHeap below (a score must always be an int32)
	scores.push([i, i]);
}

// construct a ScoreHeap with objs scores and a max length
let heap = new ScoreHeap(scores, scores.length);

console.time();

// get the next highest scoring index and remove it, then update the next entry with a random score
// 1M next() + remove() + update() each
for (let i; (i = heap.next()) != null;) {

	heap.remove(i, objs[i].i);

	if (i < objs.length - 1) {
		heap.update(i + 1, Math.floor(Math.random() * objs.length));
	}
}

console.timeEnd();

// ScoreHeap does not care about your underlying data structure.
// Its only purpose is to make retrieving, updating, and removing scored array entries as fast as possible.

Methods

constructor(indexScores, maxLength)

Make a new ScoreHeap.

indexScores An array of [index, score] to build the heap from (score must be an int32) maxLength The length of the underlying (unpassed) source array (must never expand beyond this value)

Returns a new ScoreHeap.

next()

Get the highest scoring index.

Returns the index with the highest score in the heap.

update(index, score)

Update an index in the heap (index does not have to be in the heap yet).

index Index to update (or insert) score Score of the index (must be an int32)

remove(index)

Remove an index from the heap.

index Index to remove

Returns the index passed in if successful, else undefined.

Performance

...

TODO

...

Contributing

Feel free to make changes and submit pull requests whenever.

License

ScoreHeap uses the MIT license.