使用JavaScript快速排序(Hoare分区)可视化

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“快速排序”。我们将看到如何将数组划分为两部分，以及如何获得最终的排序数组。我们还将可视化快速排序的时间复杂度。

参考：

• 快速排序
• 霍尔的分区
• JavaScript中的异步函数

方法：

• 首先，我们将使用Math.random()函数生成一个随机数组。
• 使用不同的颜色来指示要比较的元素，左分区和右分区。
• 由于该算法执行操作非常快，因此已使用setTimeout()函数来减慢该过程。
• 可以通过按“ Ctrl + R”键来生成新数组。
• 使用快速排序()函数使用hoare_partition进行排序()函数

例子：

排序之前

排序后

下面是可视化快速排序算法的程序。

index.html

  

    

  

    
    Quick Sort (Hoare's Partition)
  
  
    
    
    
    
  
    

  

style.css

* {
    margin: 0px;
    padding: 0px;
    box-sizing: border-box;
}
  
.header {
    font-size: 20px;
    text-align: center;
}
  
#array {
    background-color: white;
    height: 288px;
    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;
}
  
.block_id2 {
    position: absolute;
    color: black;
    margin-top: 22px;
    width: 100%;
    text-align: center;
}
  
.block2 {
    width: 28px;
    background-color: darkgray;
    position: absolute;
    transition: 0.2s all ease;
}
  
.block_id3 {
    position: absolute;
    color: black;
    margin-top: 1px;
    width: 100%;
    text-align: center;
}
  
#count {
    height: 20px;
    width: 598px;
    margin: auto;
}

script.js

var container = document.getElementById("array");
  
// Function to generate the array of blocks
function generatearray() {
    for (var i = 0; i < 20; i++) {
        // Return a value from 1 to 100 (both inclusive)
        var value = Math.ceil(Math.random() * 100);
  
        // 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);
    }
}
  
// Function to generate indexes
var count_container = document.getElementById("count");
  
function generate_idx() {
    for (var i = 0; i < 20; i++) {
        // Creating element div
        var array_ele2 = document.createElement("div");
  
        // Adding class 'block2' to div
        array_ele2.classList.add("block2");
  
        // Adding style to div
        array_ele2.style.height =
        `${20}px`;
        array_ele2.style.transform =
        `translate(${i * 30}px)`;
  
        //adding indexes
        var array_ele_label2 = 
        document.createElement("label");
        array_ele_label2.classList.add("block_id3");
        array_ele_label2.innerText = i;
  
        // Appending created elements to index.html
        array_ele2.appendChild(array_ele_label2);
        count_container.appendChild(array_ele2);
    }
}
  
async function hoare_partition(l, r, delay = 700) {
    var blocks = 
    document.querySelectorAll(".block");
    var pivot = 
    Number(blocks[l].childNodes[0].innerHTML);
  
    var i = l - 1;
    var j = r + 1;
  
    while (true) {
        // Find leftmost element greater than
        // or equal to pivot
        do {
            i++;
            if (i - 1 >= l) blocks[i - 1].style.backgroundColor = "red";
            blocks[i].style.backgroundColor = "yellow";
            //To wait for 700 milliseconds
            await new Promise((resolve) =>
                setTimeout(() => {
                    resolve();
                }, delay)
            );
        } while (Number(blocks[i].childNodes[0].innerHTML) < pivot);
  
        // Find rightmost element smaller than
        // or equal to pivot
        do {
            j--;
            if (j + 1 <= r) blocks[j + 1].style.backgroundColor = "green";
            blocks[j].style.backgroundColor = "yellow";
            //To wait for 700 milliseconds
            await new Promise((resolve) =>
                setTimeout(() => {
                    resolve();
                }, delay)
            );
        } while (Number(blocks[j].childNodes[0].innerHTML) > pivot);
  
        // If two pointers met.
        if (i >= j) {
            for (var k = 0; k < 20; k++) blocks[k].style.backgroundColor = "#6b5b95";
            return j;
        }
  
        //swapping ith and jth element
        var temp1 = blocks[i].style.height;
        var temp2 = blocks[i].childNodes[0].innerText;
        blocks[i].style.height = blocks[j].style.height;
        blocks[j].style.height = temp1;
        blocks[i].childNodes[0].innerText = blocks[j].childNodes[0].innerText;
        blocks[j].childNodes[0].innerText = temp2;
        //To wait for 700 milliseconds
        await new Promise((resolve) =>
            setTimeout(() => {
                resolve();
            }, delay)
        );
    }
}
  
// Asynchronous QuickSort function
async function QuickSort(l, r, delay = 100) {
    // QuickSort Algorithm
    if (l < r) {
        //Storing the index of pivot element after partition
        var pivot_idx = await hoare_partition(l, r);
        //Recursively calling quicksort for left partition
        await QuickSort(l, pivot_idx);
        //Recursively calling quicksort for right partition
        await QuickSort(pivot_idx + 1, r);
    }
}
  
// Calling generatearray function
generatearray();
  
// Calling generate_idx function
generate_idx();
  
// Calling QuickSort function
QuickSort(0, 19);

输出：