Implement A Quick Sort Algorithm In JavaScript: Step-by-Step Guide

How Do You Implement A Quick Sort Algorithm In JavaScript?

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by Alan Jackson — 10 months ago in Development 5 min. read
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If your background is linked to computer science, you must have heard this name: Quick Sort. Sorting algorithms play a crucial role in computer science. They help us organize and arrange data efficiently in a JavaScript framework. One such algorithm is to implement a quick sort algorithm in JavaScript. This sorting is known for its speed and effectiveness. In this tutorial, we’ll delve into implementing Quick Sort in JavaScript Framework.

Sorting algorithms help us arrange data in a specific order. Quick Sort stands out for its average-case time complexity and adaptability to different scenarios. Understanding Quick Sort is valuable for developers. This is because of its efficiency in sorting large datasets. It’s a divide-and-conquer algorithm that minimizes the number of comparisons and swaps. Let’s continue reading till the end to know Quick Sort and its role in a JavaScript framework.

What is Quick Sort?

Tony Hoare introduced Quick Sort in 1960. It is important to note that Quick Sort follows a divide-and-conquer strategy. In other words, it selects a pivot element from the array and divides the other elements into two parts.

The process is then applied recursively to the sub-arrays until it sorts the entire array.

There exist other algorithms like Merge Sort and Heap Sort. Meanwhile, Merge Sort has a consistent time complexity but higher space complexity. On the other hand, Heap Sort guarantees worst-case performance but can be slower.

So why choose Quick Sort over other algorithms?

Quick Sort strikes a balance. As a result, it provides good average-case time complexity with less overhead.

Quick Sort’s average time complexity is O(n log n). Therefore, this time complexity makes it efficient for large datasets.

It is important to note that the worst-case time complexity is O(n^2). This condition occurs when the pivot selection consistently results in unbalanced partitions.

Therefore, choosing an effective pivot is crucial to maintaining the algorithm’s efficiency.

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Step-By-Step Implementation

Select a code editor that should match your requirements. Popular choices include

  • Visual Studio Code
  • Sublime Text
  • Atom.

Create a new JavaScript file to add the Quick Sort implementation. Ensure that the file is properly linked to your project.

Combine the left and right sub-arrays, ensuring elements are arranged around the pivot.

function quickSort(arr) {
let pivot = arr[0];
let left = [];
let right = [];
for (let i = 1; i < arr.length; i++) {
arr[i] < pivot ? left.push(arr[i]) : right.push(arr[i]);
}
return [...quickSort(left), pivot, ...quickSort(right)];
}

Apply the quickSort function recursively to the left and right sub-arrays.

function quickSort(arr) {
let pivot = arr[0];
let left = [];
let right = [];
for (let i = 1; i < arr.length; i++) {
arr[i] < pivot ? left.push(arr[i]) : right.push(arr[i]);
}
return [...quickSort(left), pivot, ...quickSort(right)];
}

What is the Basic Structure of Quick Sort?

You will understand the basic structure once we implement it. Let’s begin.

Start by defining the quickSort function. It will handle the sorting process. Here is an example:

function quickSort(arr) {
// Implementation of algorithm
}

We must identify a base case to terminate the recursion. An array with one or zero elements is already considered sorted in basic programming languages.

function quickSort(arr) {
if (arr.length <= 1) {
return arr;
}
}

How to Partition the Array?

Choose a pivot element from the array. The selection strategy can impact the algorithm’s performance.

function quickSort(arr) {
let pivot = arr[0]; // Select the first element as the pivot
}

At this point, we divide the array into two parts.

The first part should have elements less than the pivot. The other part should have elements greater than the pivot in the best online coding courses.

function quickSort(arr) {
let pivot = arr[0];;
let left = [];
let right = [];
for (let i = 1; i < arr.length; i++) {
arr[i] < pivot ? left.push(arr[i]) : right.push(arr[i]);
}
}

Combine the sorted left and right sub-arrays. We must do it with the pivot to produce the final sorted array.

function quickSort(arr) {
let pivot = arr[0];;
let left = [];
let right = [];
for (let i = 1; i < arr.length; i++) {
arr[i] < pivot ? left.push(arr[i]) : right.push(arr[i]);
}
return [...quickSort(left), pivot, ...quickSort(right)];
}

How to Implement Recursive Calls?

Apply the quickSort function recursively to the left and right sub-arrays.

function quickSort(arr) {
let pivot = arr[0];;
let left = [];
let right = [];
for (let i = 1; i < arr.length; i++) {
arr[i] < pivot ? left.push(arr[i]) : right.push(arr[i]);
}
return [...quickSort(left), pivot, ...quickSort(right)];
}

Finally, we have to produce the final sorted array as shown below:

function quickSort(arr) {
let pivot = arr[0];;
let left = [];
let right = [];
for (let i = 1; i < arr.length; i++) {
arr[i] < pivot ? left.push(arr[i]) : right.push(arr[i]);
}
return [...quickSort(left), pivot, ...quickSort(right)];
}

How to Code the Quick Sort Algorithm?

In the final coding, we must combine all the steps into the complete quick Sort function. Here is how to do it:

function quickSort(arr) {
if (arr.length <= 1) {
return arr;
}
let pivot = arr[0];;
let left = [];
let right = [];
for (let i = 1; i < arr.length; i++) {
arr[i] < pivot ? left.push(arr[i]) : right.push(arr[i]);
}
return [...quickSort(left), pivot, ...quickSort(right)];
}

Finally, we must test our algorithm using various sample arrays:

let unsortedArray = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5];
let sortedArray = quickSort(unsortedarray);
console.log(sorted array);

How to Visualize the Algorithm?

Here are some best practices to visualize and inspect your Quick Sort algorithm:

  • Use visualization tools like console logs or debugging tools. These options help us understand the flow of the algorithm.
  • Interestingly, visualizing the recursive calls and array partitions can enhance comprehension.
  • We can also set breakpoints to pause the running and observe code at a specific point.
  • We must remember to compare the performance of Quick Sort with other sorting algorithms in real-time scenarios.
  • Since this algorithm is more effective for large datasets, we must visualize the efficiency of Quick Sort in large datasets.

What Are Optimizations and Best Practices for Quick Sort?

One of the best optimization techniques is to follow a randomized pivot selection strategy. This helps avoid worst-case scenarios.

Address challenges due to duplicate elements in the array.

Finally, understand when to use Quick Sort based on the dataset’s characteristics.

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What Are the Application and Use Cases of Quick Sort?

Applications of Quick Sort are listed below:

  • Quick Sort’s exceptional speed and low complexity make it essential for optimizing performance in databases and search engines.
  • Developers leverage its prowess for sorting vast datasets swiftly. It helps us enhance system responsiveness.
  • Quick Sort is a preferred sorting algorithm across industries.
  • Whether managing diverse data or ensuring rapid information retrieval, Quick Sort is a robust solution with broad practical applications.
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Conclusion

In the above article, we implemented the Quick Sort algorithm in the JavaScript wizard. We also talked about the application of the Quick Sort algorithm. At the same time, we also discussed the optimization techniques and best practices for using the Quick Sort algorithm in JavaScript. JavaScript frameworks use this algorithm at some point to maintain their efficiency. If you want to know more about it, let us know in the comments.

FAQs

How Do I Choose a Good Pivot Element?

It is recommended to choose a pivot randomly to prevent the worst-case scenario.

Can Quick Sort Handle Arrays With Different Data Types?

This algorithm is more suitable for large data sets.

Are There Real-World Applications for Quick Sort?

Quick Sort algorithm helps us achieve a responsive system in Real-world applications.

What Is the Importance of Quick Sort?

It is one of the most effective algorithms with higher speed and efficiency.

Alan Jackson

Alan is content editor manager of The Next Tech. He loves to share his technology knowledge with write blog and article. Besides this, He is fond of reading books, writing short stories, EDM music and football lover.

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