https://github.com/pathikrit/arraydeque-talk
https://github.com/pathikrit/arraydeque-talk
Last synced: 11 months ago
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- Host: GitHub
- URL: https://github.com/pathikrit/arraydeque-talk
- Owner: pathikrit
- Created: 2018-06-09T21:45:01.000Z (about 8 years ago)
- Default Branch: master
- Last Pushed: 2018-06-16T20:38:09.000Z (about 8 years ago)
- Last Synced: 2025-01-29T07:20:30.475Z (over 1 year ago)
- Language: Scala
- Homepage: https://slides.com/pathikrit/arraydeque#/
- Size: 11 MB
- Stars: 0
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
ArrayDeque
----------
To run the code:
```shell
sbt "~runMain Demo"
```
Prior discussion:
https://contributors.scala-lang.org/t/using-circular-buffers-as-mutable-arraybuffer/454
SI-10167: https://issues.scala-lang.org/browse/SI-10167
ArrayDeque's (implemented using a growable circular buffers using modular arithmetic for indexing) are strictly better data structures than vanilla ArrayBuffers.
This improves on `java.util.ArrayDeque` by providing an O(1) `get(idx)` and also providing faster `insertAt(idx)` and `deleteAt(idx)` operations.
This implementation adds `O(1)` `append`, `prepend`, `removeHead`, `removeTail`, `get`, `update` and `clear` APIs.
We also provide proof of concept replacement implementations of mutable data structures like stack, queues and buffers with ArrayDeque here.
Preliminary benchmarks prove that this data structure can suitably replace `mutable.ArrayBuffer`
```
===============[Insert lots of items]=================
ArrayDeque: 956.76 ms
ArrayBuffer: 2473.36 ms
===============[Drop some items from an head index]=================
ArrayDeque: 1.25 ms
ArrayBuffer: 7.65 ms
===============[Drop some items from a tail index]=================
ArrayDeque: 0.28 ms
ArrayBuffer: 2.54 ms
===============[Append lots of items one by one]=================
ArrayDeque: 2222.13 ms
ArrayBuffer: 3576.63 ms
===============[Prepend few items one by one]=================
ArrayDeque: 1.33 ms
ArrayBuffer: 8699.13 ms
===============[Prepend lots of items at once]=================
ArrayDeque: 462.76 ms
ArrayBuffer: 2124.02 ms
===============[Random indexing]=================
ArrayDeque: 84.02 ms
ArrayBuffer: 81.62 ms
===============[Insert items near head]=================
ArrayDeque: 1429.52 ms
ArrayBuffer: 2980.46 ms
===============[Reversal]=================
ArrayDeque: 378.69 ms
ArrayBuffer: 491.46 ms
===============[Insert items near tail]=================
ArrayDeque: 2504.20 ms
ArrayBuffer: 8588.98 ms
===============[Sliding]=================
ArrayDeque: 157.25 ms
ArrayBuffer: 1591.47 ms
===============[toArray]=================
ArrayDeque: 181.07 ms
ArrayBuffer: 194.55 ms
===============[Clear lots of items]=================
ArrayDeque: 48.34 ms
ArrayBuffer: 28.62 ms
```
To run benchmarks:
```shell
sbt "test/runMain scala.collection.mutable.ArrayDequeBenchmark"
```