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Shell Sort Visualizer using JavaScript

Last Updated : 10 Apr, 2023
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Shell Sort is mainly a variation of Insertion Sort. The idea of shell sort is to allow the exchange of far items. In order to know more about it. Please refer to Shell Sort.

An algorithm like Shell Sort can be easily understood by visualizing instead of long codes. In this article, Shell Sort Visualizer is implemented using HTML, CSS & JavaScript.

Pre-requisites:

Approach:

  • Button Generate New Array generates an array of random values using the Math.random() function and a bar corresponding to that value in terms of height.
  • Different colors are used to indicate which elements are unsorted(sky-blue), compared(darkblue) & sorted(lightgreen).
  • Button Shell Sort sorts the elements using the selection sort algorithm.
  • Finally, elements are sorted.

 Example: Click on ‘Generate New Array’ button to generate a new random array. Click on the ‘Shell Sort’ button to perform Visualization.

HTML




<!DOCTYPE html>
<html lang="en">
<!-- Head Section -->
<head>
    <meta charset="UTF-8" />
    <meta name="viewport" 
          content="width=device-width, 
          initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" 
          content="ie=edge" />
  
    <!-- title -->
    <title>Shell Sort Visualizer using JavaScript</title>
  
    <!-- linking style.css -->
    <link href="style.css" rel="stylesheet" />
</head>
  
<!-- Body Section -->
  
<body>
    <section class="head">Shell Sort</section>
    <section class="data-container"></section>
    <section id="ele"></section>
    <div style="margin: auto; width: fit-content">
  
        <!-- "Generate New Array" button -->
        <button class="btn1" onclick="generate()" 
                id="Button1">
            Generate New Array
        </button>
  
        <!-- "Shell Sort" button -->
        <button class="btn2" onclick="ShellSort(),disable()" 
                id="Button2">Shell Sort</button>
    </div>
  
    <!-- linking script.js -->
    <script src="script.js"></script>
</body>
</html>


Filename: style.css

css




.mySlides {
  display: none;
}
body {
  background-color: rgb(255, 235, 211);
  font-family: Verdana, sans-serif;
}
.head {
  margin-top: 20px;
  margin-right: 20vw;
  margin-left: 20vw;
  text-align: center;
  font-size: 30px;
  background-color: #6f459e;
  color: white;
  border-radius: 19px;
  font-weight: bolder;
}
.data-container {
  width: 600px;
  height: 364px;
  position: relative;
  margin: 0 auto;
}
.bar {
  width: 28px;
  position: absolute;
  left: 0;
  bottom: 0;
  background-color: rgb(0, 183, 255);
  transition: 0.2s all ease;
}
.bar__id {
  position: absolute;
  top: -24px;
  width: 100%;
  text-align: center;
}
.btn1 {
  padding: 12px;
  font-weight: bolder;
  background-color: #6f459e;
  border-radius: 10px;
  color: white;
  font-size: 16px;
  border: white;
  margin-top: 1vw;
  margin-right: 1vw;
}
.btn2 {
  padding: 12px;
  font-weight: bolder;
  background-color: #6f459e;
  border-radius: 10px;
  color: white;
  font-size: 16px;
  border: white;
}
#ele {
  text-align: center;
  height: 35px;
}


Filename: script.js

javascript




const container = document.querySelector(".data-container");
  
// Function to generate bars
function generatebars(num = 20) {
  
    // For loop to generate 20 bars
    for (let i = 0; i < num; i += 1) {
  
        // To generate random values from 1 to 100
        const value = Math.floor(Math.random() * 100) + 1;
  
        // To create element "div"
        const bar = document.createElement("div");
  
        // To add class "bar" to "div"
        bar.classList.add("bar");
  
        // Provide height to the bar
        bar.style.height = `${value * 3}px`;
  
        // Translate the bar towards positive X axis
        bar.style.transform = `translateX(${i * 30}px)`;
  
        // To create element "label"
        const barLabel = document.createElement("label");
  
        // To add class "bar_id" to "label"
        barLabel.classList.add("bar__id");
  
        // Assign value to "label"
        barLabel.innerHTML = value;
  
        // Append "Label" to "div"
        bar.appendChild(barLabel);
  
        // Append "div" to "data-container div"
        container.appendChild(bar);
    }
}
  
// Asynchronous function to perform "Shell Sort"
async function ShellSort(delay = 600) {
    let bars = document.querySelectorAll(".bar");
  
    for (var i = 10; i > 0; i = Math.floor(i / 2)) {
  
        // To pause the execution of code
        // for 300 milliseconds
        await new Promise((resolve) =>
            setTimeout(() => {
                resolve();
            }, 300)
        );
  
        for (var j = i; j < 20; j++) {
            var temp = parseInt(
                bars[j].childNodes[0].innerHTML);
            var k;
  
            var temp1 = bars[j].style.height;
            var temp2 = bars[j].childNodes[0].innerText;
  
            for (
                k = j;
                k >= i && parseInt(bars[k - i]
                    .childNodes[0].innerHTML) > temp;
                k -= i
            ) {
                bars[k].style.height 
                        = bars[k - i].style.height;
  
                bars[k].childNodes[0].innerText = 
                    bars[k - i].childNodes[0].innerText;
  
                // To pause the execution of code
                // for 300 milliseconds
                await new Promise((resolve) =>
                    setTimeout(() => {
                        resolve();
                    }, 300)
                );
            }
  
            // Provide darkblue color to the jth bar
            bars[j].style.backgroundColor = "darkblue";
  
            // Provide darkblue color to the kth bar
            bars[k].style.backgroundColor = "darkblue";
            bars[k].style.height = temp1;
            bars[k].childNodes[0].innerText = temp2;
  
            // To pause the execution of code for
            // 300 milliseconds
            await new Promise((resolve) =>
                setTimeout(() => {
                    resolve();
                }, 600)
            );
  
            // Provide skyblue color to the jth bar
            bars[j].style.backgroundColor = "rgb(0, 183, 255)";
  
            // Provide skyblue color to the kth bar
            bars[k].style.backgroundColor = "rgb(0, 183, 255)";
  
            // To pause the execution of code for
            // 300 milliseconds
            await new Promise((resolve) =>
                setTimeout(() => {
                    resolve();
                }, 300)
            );
        }
    }
    for (var x = 0; x < 20; x++) {
        bars[x].style.backgroundColor 
            = "rgb(49, 226, 13)";
    }
  
    // To enable the button "Generate New Array"
    // after final(sorted)
    document.getElementById("Button1")
            .disabled = false;
  
    document.getElementById("Button1")
        .style.backgroundColor = "#6f459e";
  
    // To enable the button "Shell Sort"
    // after final(sorted)
    document.getElementById("Button2").disabled = false;
    document.getElementById("Button2")
        .style.backgroundColor = "#6f459e";
}
  
// Call "generatebars()" function
generatebars();
  
// Function to generate new random array
function generate() {
    window.location.reload();
}
  
// Function to disable the button
function disable() {
    // To disable the button "Generate New Array"
    document.getElementById("Button1").disabled = true;
    document.getElementById("Button1")
        .style.backgroundColor = "#d8b6ff";
  
    // To disable the button "Shell Sort"
    document.getElementById("Button2").disabled = true;
    document.getElementById("Button2")
        .style.backgroundColor = "#d8b6ff";
}


Output:



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