Benchmark: Map vs Two Arrays

Script Preparation code:

const size = 3000
var input = new Array(size).fill().map(() => Math.round(size / 3 * Math.random()))

function getPairCount() {
    const pairMap = new Map()
    let pairs = 0
    input.forEach((number) => {
        if (!pairMap.has(number)) pairMap.set(number, true)
        else {
            pairMap.delete(number)
            pairs++
        }
    })
    return pairs;
}

function countPairs() {
    let nums = [];
    let count = [];
    input.forEach((num) => {
        if (!nums.includes(num)) {
            nums.push(num);
            count.push(0);
        }
        count[nums.indexOf(num)] += 1;
    });
    let pairs = 0;
    count.forEach((num) => {
        pairs += Math.floor(num / 2);
    })
    return pairs;
}

function findPairs() {
    const map = new Map()
    let pairs = 0
    input.forEach(num => {
        if (map.get(num)) {
            pairs += 1
            map.set(num, false)
        } else map.set(num, true)
    })
    return pairs
}

Tests:

Map (delete)
getPairCount()
Two Arrays
countPairs()
Map (set false)
findPairs()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map (delete)
Two Arrays
Map (set false)

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition:**

The benchmark is designed to compare three different approaches for counting pairs in an array:

1. Using a `Map` data structure ( `getPairCount()` )
2. Using two separate arrays ( `countPairs()`)
3. Using a `Map` with the `delete` method and a boolean flag ( `findPairs()`)

**Options compared:**

* The three approaches are being compared in terms of performance, specifically the number of executions per second.
* Each approach is executed for the same input data.

**Pros and Cons:**

1. **Using a Map (`getPairCount()`):**
	* Pros:
		+ Efficiently handles duplicate elements.
		+ Easy to implement.
	* Cons:
		+ Requires two additional operations ( `has` and `delete` ) to maintain the map, which might impact performance in some cases.
2. **Using two separate arrays (`countPairs()`):**
	* Pros:
		+ Simple and easy to understand.
	* Cons:
		+ Less efficient than using a `Map`, as it requires multiple array operations ( `indexOf` and `push` ) for each element.
3. **Using a Map with the `delete` method and a boolean flag (`findPairs()`):**
	* Pros:
		+ Optimized for performance, as it only requires two map operations ( `get` and `set` ).
	* Cons:
		+ Requires an additional boolean flag to track deleted elements, which might add complexity.

**Library/Features:**

None mentioned in the provided benchmark definition. However, using a `Map` data structure is a native JavaScript feature that's been available since ECMAScript 2009 (ECMA-262, 5th edition).

**Special JS features/syntax:**

The benchmark uses arrow functions (`() =>`) and template literals (`\r\n`), which are modern JavaScript features introduced in ECMAScript 2015 (ECMA-262, 6th edition). These features are widely supported by most JavaScript engines and are considered a part of the standard language.

**Other alternatives:**

If you're interested in exploring alternative approaches for counting pairs, here are a few options:

* Using an object with keys instead of a `Map`: This approach would require iterating over the input array twice, once to populate the object and once to count pairs.
* Using a binary search tree data structure: This approach would require implementing a custom binary search tree implementation, which could be more complex than using a `Map`.
* Using a specialized library or framework for data analysis: There are libraries like Lodash or Mathjs that provide optimized functions for common data manipulation tasks, including counting pairs.

Related benchmarks:

Map vs Two Arrays (version: 0)

Comparing performance of: Map (delete) vs Two Arrays vs Map (set false)

Created: 5 years ago by: Registered User

Jump to the latest result

Map (delete)

Two Arrays

Map (set false)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):