Selection sort
Selection sort is one of the most stable sorting algorithms. When using it, the smaller the data size, the better. Theoretically speaking, selection sort may also be the most common method that most people think of when sorting.
Selection sort is a simple and intuitive sorting algorithm. How it works is:
Traverse an array, and in the process, find the maximum value and its position in the array. Then "swap the position" of the unit with the maximum value with the last unit of the array. After doing this, the maximum value in the array must be placed at the last position.
Continue to traverse the remaining data in the above process and do the same thing. At this time, the maximum value of the remaining part can also be placed at the last position of the remaining part - it is the penultimate position as a whole. s position.
So on and so forth. . . . . .
Illustration:
22 | 15 | 23 | ||||
18 | 12 | 15 | 9 | 23 | ||
18 | 9 | 12 | 15 | 22 | 23 | |
15 | 9 | 12 | 18 | 22 | 23 | |
12 | 9 | 15 | 18 | 22 | 23 | ##The fifth trip |
12 | 15 | 18 | 22 | 23 |
<?php
$arr1 = array(18,22,12,15,23,9);
$n = count($arr1);
for ($i=0; $i < $n-1; $i++) {
//找最大值
$max = $arr1[0];
$max_key = 0;
for ($k=0; $k < $n - $i; $k++) {
if ($arr1[$k] > $max) {
$max = $arr1[$k];
$max_key = $k;
}
}
//交换
$temp = $arr1[$max_key];
$arr1[$max_key] = $arr1[$n-1-$i];
$arr1[$n-1-$i] = $temp;
}
Summary of the rules:
1. To find the largest one from beginning to end value (and subscript), and the number of times to exchange is $n-1, $n is the length of the array 2. What each time needs to do is: a) find the maximum value, right) and Exchange the maximum value with the last item of this trip;
3. The number of data to find the maximum value in each trip is 1 less than the previous trip, of which the first trip has $n indivual.
The above is the detailed content of Detailed analysis of selection sort algorithm. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

WebStorm Mac version
Useful JavaScript development tools

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

SublimeText3 English version
Recommended: Win version, supports code prompts!
