Shell Sort Algorithm in DSA Javascript - Build from Scratch

Shell Sort Algorithm

📖 Scenario: You are working on a small app that sorts a list of numbers efficiently. You will implement the Shell Sort algorithm step-by-step to understand how it works.

🎯 Goal: Build a JavaScript program that sorts an array of numbers using the Shell Sort algorithm and prints the sorted array.

📋 What You'll Learn

Create an array called numbers with the exact values: [23, 12, 1, 8, 34, 54, 2, 3]

Create a variable called n that stores the length of the numbers array

Implement the Shell Sort algorithm using a while loop to reduce the gap and a nested for loop to sort elements

Print the sorted numbers array at the end

💡 Why This Matters

🌍 Real World

Shell Sort is used in situations where a simple, efficient sorting algorithm is needed for medium-sized arrays, such as sorting user data or small datasets in web apps.

💼 Career

Understanding Shell Sort helps in grasping how sorting algorithms optimize performance, which is useful for software developers working on data processing and optimization tasks.

1

Create the initial array

Create an array called numbers with these exact values: [23, 12, 1, 8, 34, 54, 2, 3]

DSA Javascript

// Create the array called numbers with the given values
// Your code here

Hint

Use const numbers = [23, 12, 1, 8, 34, 54, 2, 3]; to create the array.

2

Set up the length and initial gap

Create a variable called n that stores the length of the numbers array and create a variable called gap initialized to Math.floor(n / 2)

DSA Javascript

const numbers = [23, 12, 1, 8, 34, 54, 2, 3];
// Create variables n and gap
// Your code here

Hint

Use const n = numbers.length; and let gap = Math.floor(n / 2);

3

Implement the Shell Sort core logic

Write a while loop that runs while gap > 0. Inside it, write a for loop with variable i from gap to n. Inside the for loop, create a variable temp equal to numbers[i] and a variable j equal to i. Then use a while loop to shift elements greater than temp by gap positions. After shifting, assign temp to numbers[j]. Finally, reduce gap by half using Math.floor(gap / 2).

DSA Javascript

const numbers = [23, 12, 1, 8, 34, 54, 2, 3];
const n = numbers.length;
let gap = Math.floor(n / 2);
// Implement the Shell Sort algorithm
// Your code here

Hint

Use nested loops: a while loop for gap, a for loop for index, and an inner while loop to shift elements.

4

Print the sorted array

Write a console.log(numbers) statement to print the sorted numbers array.

DSA Javascript

const numbers = [23, 12, 1, 8, 34, 54, 2, 3];
const n = numbers.length;
let gap = Math.floor(n / 2);

while (gap > 0) {
    for (let i = gap; i = gap && numbers[j - gap] > temp) {
            numbers[j] = numbers[j - gap];
            j -= gap;
        }
        numbers[j] = temp;
    }
    gap = Math.floor(gap / 2);
}
// Print the sorted numbers array
// Your code here

Hint

Use console.log(numbers); to print the sorted array.