使用 JavaScript 的二分搜索法可视化
原文:https://www . geesforgeks . org/binary-search-visualization-use-JavaScript/
GUI(图形用户界面)比程序更有助于理解。在本文中，我们将使用 JavaScript 可视化二分搜索法。我们将看到元素是如何在二分搜索法遍历的，直到找到给定的元素。我们还将想象二分搜索法的时间复杂性。
参考:
进场:
- 首先，我们将使用 Math.random() 函数生成一个随机数组，然后使用 sort() 函数对其进行排序。
- 不同的颜色用于指示当前时间哪个元素正在被遍历。
- 由于算法的运算速度非常快， setTimeout() 功能被用来减缓进程。
- 按“Ctrl+R”键可生成新数组。
- 使用 BinarySearch()函数执行搜索。
示例:
搜索前
搜索后
下面是可视化 【二分搜索法】 算法的程序。
文件名:index.html
超文本标记语言
<!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>
文件名:style.css
半铸钢ˌ钢性铸铁(Cast Semi-Steel)
* {
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: 0.2s all ease;
}
.block_id {
position: absolute;
color: black;
margin-top: -20px;
width: 100%;
text-align: center;
}
文件名:script.js
java 描述语言
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 voilet
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();
输出:
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