GUI(Graphical User Interface) helps in better understanding than programs. In this article, we will visualize Binary Search using JavaScript. We will see how the elements are being traversed in Binary Search until the given element is found. We will also visualize the time complexity of Binary Search.
Reference:
Approach:
- First, we will generate a random array using Math.random() function and then sort it using sort() function.
- Different color is used to indicate which element is being traversed at current time.
- Since the algorithm performs the operation very fast, the setTimeout() function has been used to slow down the process.
- New array can be generated by pressing the “Ctrl+R” key.
- The searching is performed using BinarySearch() function.
Example:
Below is the program to visualize the Binary Search algorithm.
Filename: index.html
HTML
<!DOCTYPE html> < html lang = "en" > < head > < meta charset = "UTF-8" /> < meta name = "viewport" content = "width=device-width, initial-scale=1.0" /> < link rel = "stylesheet" href = "style.css" /> </ head > < body > < br /> < p class = "header" >Binary Search</ p > < div id = "array" ></ div > < br />< br /> < div style = "text-align: center" > < label for = "fname" > Number to be Searched: </ label > < input type = "text" id = "fname" name = "fname" /> < br />< br /> < button id = "btn" onclick = "BinarySearch()" >Search</ button > < br /> < br /> < div id = "text" ></ div > </ div > < script src = "script.js" ></ script > </ body > </ html > |
Filename: style.css
CSS
* { margin : 0px ; padding : 0px ; box-sizing: border-box; } .header { font-size : 35px ; text-align : center ; } #array { background-color : white ; height : 305px ; width : 598px ; margin : auto ; position : relative ; margin-top : 64px ; } . block { width : 28px ; background-color : #6b5b95 ; position : absolute ; bottom : 0px ; transition: 0.2 s all ease; } .block_id { position : absolute ; color : black ; margin-top : -20px ; width : 100% ; text-align : center ; } |
Filename: script.js
Javascript
var container = document.getElementById( "array" ); // Function to generate the array of blocks function generatearray() { // Creating an array var arr = []; // Filling array with random values for ( var i = 0; i < 20; i++) { // Return a value from 1 to 100 (both inclusive) var val = Number(Math.ceil(Math.random() * 100)); arr.push(val); } // Sorting Array in ascending order arr.sort( function (a, b) { return a - b; }); for ( var i = 0; i < 20; i++) { var value = arr[i]; // Creating element div var array_ele = document.createElement( "div" ); // Adding class 'block' to div array_ele.classList.add( "block" ); // Adding style to div array_ele.style.height = `${value * 3}px`; array_ele.style.transform = `translate(${i * 30}px)`; // Creating label element for displaying // size of particular block var array_ele_label = document.createElement( "label" ); array_ele_label.classList.add( "block_id" ); array_ele_label.innerText = value; // Appending created elements to index.html array_ele.appendChild(array_ele_label); container.appendChild(array_ele); } } // Asynchronous BinarySearch function async function BinarySearch(delay = 300) { var blocks = document.querySelectorAll( ".block" ); var output = document.getElementById( "text" ); //Extracting the value of the element to be searched var num = document.getElementById( "fname" ).value; //Colouring all the blocks violet for ( var i = 0; i < blocks.length; i += 1) { blocks[i].style.backgroundColor = "#6b5b95" ; } output.innerText = "" ; // BinarySearch Algorithm var start = 0; var end = 19; var flag = 0; while (start <= end) { //Middle index var mid = Math.floor((start + end) / 2); blocks[mid].style.backgroundColor = "#FF4949" ; //Value at mid index var value = Number(blocks[mid].childNodes[0].innerHTML); // To wait for .1 sec await new Promise((resolve) => setTimeout(() => { resolve(); }, delay) ); //Current element is equal to the element //entered by the user if (value == num) { output.innerText = "Element Found" ; blocks[mid].style.backgroundColor = "#13CE66" ; flag = 1; break ; } //Current element is greater than the element //entered by the user if (value > num) { end = mid - 1; blocks[mid].style.backgroundColor = "#6b5b95" ; } else { start = mid + 1; blocks[mid].style.backgroundColor = "#6b5b95" ; } } if (flag === 0) { output.innerText = "Element Not Found" ; } } // Calling generatearray function generatearray(); |
Output:
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