首页 php教程 php手册 浅谈php随机不重复数的两种算法

浅谈php随机不重复数的两种算法

Jun 06, 2016 pm 07:50 PM
php 复数 引入 算法 随机

先引入别人的一个秒表计时类(counttime.class.php): 1.先看第一个例子(大数中取少数): 1 ? 2 /* 3 @描述: Stopwatch这个类用户获取脚本执行时间 4 @作者: Klesti Hoxha klesti@gmail.com 5 */ 6 7 class Stopwatch { 8 private $start ; 9 private $en

先引入别人的一个秒表计时类(counttime.class.php):

1.先看第一个例子(大数中取少数):

<span> 1</span> 
<span> 2</span> <span>/*</span>
<span> 3</span> <span>@描述: Stopwatch这个类用户获取脚本执行时间
</span><span> 4</span> <span>@作者: Klesti Hoxha <klesti>
</klesti></span><span> 5</span> <span>*/</span>
<span> 6</span> 
<span> 7</span> <span>class</span><span> Stopwatch {
</span><span> 8</span> <span>private</span> <span>$start</span><span>;
</span><span> 9</span> <span>private</span> <span>$end</span><span>;
</span><span>10</span> <span>private</span> <span>$markup_start</span> = <span>array</span><span>();
</span><span>11</span> <span>private</span> <span>$markup_end</span> = <span>array</span><span>();
</span><span>12</span> 
<span>13</span> <span>function</span> __construct(<span>$markup</span>=<span>false</span><span>) {
</span><span>14</span> <span>$this</span>->start(<span>$markup</span><span>);
</span><span>15</span> <span>}
</span><span>16</span> 
<span>17</span> <span>public</span> <span>function</span> start(<span>$markup</span>=<span>false</span><span>) {
</span><span>18</span> <span>if</span> (!<span>$markup</span><span>) {
</span><span>19</span> <span>$this</span>->start = <span>$this</span>-><span>getmicrotime();
</span><span>20</span> } <span>else</span><span> {
</span><span>21</span> <span>$this</span>->markup_start[<span>$markup</span>] = <span>$this</span>-><span>getmicrotime();
</span><span>22</span> <span>}
</span><span>23</span> <span>}
</span><span>24</span> 
<span>25</span> <span>public</span> <span>function</span> stop(<span>$markup</span>=<span>false</span><span>) {
</span><span>26</span> <span>if</span> (!<span>$markup</span><span>) {
</span><span>27</span> <span>$this</span>-><span>end</span> = <span>$this</span>-><span>getmicrotime();
</span><span>28</span> } <span>else</span><span> {
</span><span>29</span> <span>$this</span>->markup_end[<span>$markup</span>] = <span>$this</span>-><span>getmicrotime();
</span><span>30</span> <span>}
</span><span>31</span> <span>return</span> <span>$this</span>->getDuration(<span>$markup</span><span>);
</span><span>32</span> <span>}
</span><span>33</span> 
<span>34</span> <span>public</span> <span>function</span> getDuration(<span>$markup</span>=<span>false</span><span>) {
</span><span>35</span>     <span>if</span> (!<span>$markup</span><span>)
</span><span>36</span> <span>     {
</span><span>37</span>         <span>return</span> <span>number_format</span>(<span>$this</span>-><span>end</span>-<span>$this</span>->start,4<span>);
</span><span>38</span>     } <span>else</span><span> {
</span><span>39</span>         <span>return</span> <span>number_format</span>(<span>$this</span>->markup_end[<span>$markup</span>]-<span>$this</span>->markup_start[<span>$markup</span>],4<span>);
</span><span>40</span> <span>    }
</span><span>41</span> <span>}
</span><span>42</span> 
<span>43</span> <span>public</span> <span>function</span> <span>reset</span>(<span>$markup</span><span>) {
</span><span>44</span> <span>if</span> (!<span>$markup</span><span>) {
</span><span>45</span> <span>$this</span>->start = 0<span>;
</span><span>46</span> <span>$this</span>-><span>end</span> = 0<span>;
</span><span>47</span> <span>$this</span>->markup_start = <span>array</span><span>();
</span><span>48</span> <span>$this</span>->markup_end = <span>array</span><span>();
</span><span>49</span> } <span>else</span><span> {
</span><span>50</span> <span>$this</span>->markup_start[<span>$markup</span>] = 0<span>;
</span><span>51</span> <span>$this</span>->markup_end[<span>$markup</span>] = 0<span>;
</span><span>52</span> <span>}
</span><span>53</span> <span>}
</span><span>54</span> 
<span>55</span> <span>private</span> <span>function</span><span> getmicrotime(){
</span><span>56</span> <span>list</span>(<span>$usec</span>, <span>$sec</span>) = <span>explode</span>(" ",<span>microtime</span><span>());
</span><span>57</span> <span>return</span> ((<span>float</span>)<span>$usec</span> + (<span>float</span>)<span>$sec</span><span>);
</span><span>58</span> <span>}
</span><span>59</span> 
<span>60</span> <span>}
</span><span>61</span> ?>
登录后复制

测试的两种方法如下:

<span> 1</span> <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<span> 2</span> <span>php
</span><span> 3</span> <span>require</span> "counttime.class.php";<span>//</span><span>把类文件引用进来,根据你的实际情况来确定路径,这里是在同级目录</span>
<span> 4</span> <span>$s</span> = <span>new</span><span> Stopwatch();
</span><span> 5</span> 
<span> 6</span> <span>$s</span>->start("div1"<span>);
</span><span> 7</span> <span>//</span><span>range 是将1到100 列成一个数组</span>
<span> 8</span> <span>$numbers</span> = <span>range</span> (1,1000000<span>);
</span><span> 9</span> <span>//</span><span>shuffle 将数组顺序随即打乱</span>
<span>10</span> <span>shuffle</span> (<span>$numbers</span><span>);
</span><span>11</span> <span>//</span><span>array_slice 取该数组中的某一段</span>
<span>12</span> <span>$no</span>=30<span>;
</span><span>13</span> <span>$result</span> = <span>array_slice</span>(<span>$numbers</span>,0,<span>$no</span><span>);
</span><span>14</span> <span>for</span> (<span>$i</span>=0;<span>$i</span>$no;<span>$i</span>++<span>){
</span><span>15</span> <span>echo</span> <span>$result</span>[<span>$i</span>]."<br>"<span>;
</span><span>16</span> <span>}
</span><span>17</span> <span>echo</span> "第一个测验方法结束<br><br>"<span>;
</span><span>18</span> <span>$s</span>->stop("div1"<span>);
</span><span>19</span> 
<span>20</span> <span>$s</span>->start("div2"<span>);
</span><span>21</span> <span>function</span> unique_rand(<span>$min</span>, <span>$max</span>, <span>$num</span><span>)
</span><span>22</span> <span>{
</span><span>23</span>         <span>$count</span> = 0<span>;
</span><span>24</span>         <span>$return</span> = <span>array</span><span>();
</span><span>25</span>         <span>while</span> (<span>$count</span> $num<span>) {
</span><span>26</span>             <span>$return</span>[] = <span>mt_rand</span>(<span>$min</span>, <span>$max</span><span>);
</span><span>27</span>             <span>$return</span> = <span>array_flip</span>(<span>array_flip</span>(<span>$return</span><span>));
</span><span>28</span>             <span>$count</span> = <span>count</span>(<span>$return</span><span>);
</span><span>29</span> <span>        }
</span><span>30</span>         <span>shuffle</span>(<span>$return</span><span>);
</span><span>31</span>         <span>return</span> <span>$return</span><span>;
</span><span>32</span> <span>}
</span><span>33</span> 
<span>34</span>     <span>$arr</span> = unique_rand(1, 100000000000, 30<span>);
</span><span>35</span>     <span>$result</span> = ''<span>;
</span><span>36</span>     <span>for</span>(<span>$i</span>=0; <span>$i</span> count(<span>$arr</span>);<span>$i</span>++<span>)
</span><span>37</span> <span>    {
</span><span>38</span>         <span>$result</span> = <span>$arr</span>[<span>$i</span><span>];
</span><span>39</span>         <span>echo</span> <span>$result</span>."<br>"<span>;
</span><span>40</span> <span>    }
</span><span>41</span>     <span>$s</span>->stop("div2"<span>);
</span><span>42</span> 
<span>43</span> 
<span>44</span> <span>//</span><span>输出时间</span>
<span>45</span> <span>echo</span> "div 1 Duration: " . <span>$s</span>->getDuration("div1") . " seconds.<br>"<span>;
</span><span>46</span> <span>echo</span> "div 2 Duration: " . <span>$s</span>->getDuration("div2") . " seconds.<br>"<span>;
</span><span>47</span> ?>
登录后复制

结果为:

<span> 1</span> 413537
<span> 2</span> 198587
<span> 3</span> 60611
<span> 4</span> 599544
<span> 5</span> 946241
<span> 6</span> 462853
<span> 7</span> 570943
<span> 8</span> 980260
<span> 9</span> 717416
<span>10</span> 969324
<span>11</span> 292403
<span>12</span> 614443
<span>13</span> 769469
<span>14</span> 151951
<span>15</span> 167883
<span>16</span> 308727
<span>17</span> 342706
<span>18</span> 955659
<span>19</span> 112311
<span>20</span> 329008
<span>21</span> 182668
<span>22</span> 330600
<span>23</span> 921966
<span>24</span> 993143
<span>25</span> 369227
<span>26</span> 747066
<span>27</span> 793185
<span>28</span> 347872
<span>29</span> 439016
<span>30</span> 428600
<span>31</span> <span>第一个测验方法结束
</span><span>32</span> 
<span>33</span> 649589727
<span>34</span> 450823813
<span>35</span> 324717181
<span>36</span> 44553762
<span>37</span> 375669657
<span>38</span> 37128612
<span>39</span> 25135327
<span>40</span> 468454185
<span>41</span> 73395357
<span>42</span> 753960006
<span>43</span> 214455797
<span>44</span> 5367614
<span>45</span> 1153263961
<span>46</span> 17803441
<span>47</span> 669057198
<span>48</span> 55366324
<span>49</span> 1117343950
<span>50</span> 203530485
<span>51</span> 1160930064
<span>52</span> 326487914
<span>53</span> 565471236
<span>54</span> 7068443
<span>55</span> 846955001
<span>56</span> 832037489
<span>57</span> 1067813034
<span>58</span> 219239595
<span>59</span> 1069795964
<span>60</span> 1049898846
<span>61</span> 926301266
<span>62</span> 197341539
<span>63</span> div 1 Duration: 0.5800 seconds.
<span>64</span> div 2 Duration: 0.0000 seconds.
登录后复制

 

结论:对于从大量数据中取少量数据,显然第二种比较快。

 

2.在来看看从大数中取大数:

<span> 1</span> <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<span> 2</span> <span>php
</span><span> 3</span> <span>require</span> "counttime.class.php";<span>//</span><span>把类文件引用进来,根据你的实际情况来确定路径,这里是在同级目录</span>
<span> 4</span> <span>$s</span> = <span>new</span><span> Stopwatch();
</span><span> 5</span> 
<span> 6</span> <span>$s</span>->start("div1"<span>);
</span><span> 7</span> <span>//</span><span>range 是将1到100 列成一个数组</span>
<span> 8</span> <span>$numbers</span> = <span>range</span> (1,1000000<span>);
</span><span> 9</span> <span>//</span><span>shuffle 将数组顺序随即打乱</span>
<span>10</span> <span>shuffle</span> (<span>$numbers</span><span>);
</span><span>11</span> <span>//</span><span>array_slice 取该数组中的某一段</span>
<span>12</span> <span>$no</span>=10000<span>;
</span><span>13</span> <span>$result</span> = <span>array_slice</span>(<span>$numbers</span>,0,<span>$no</span><span>);
</span><span>14</span> <span>for</span> (<span>$i</span>=0;<span>$i</span>$no;<span>$i</span>++<span>){
</span><span>15</span> <span>echo</span> <span>$result</span>[<span>$i</span>]."<br>"<span>;
</span><span>16</span> <span>}
</span><span>17</span> <span>echo</span> "第一个测验方法结束<br><br>"<span>;
</span><span>18</span> <span>$s</span>->stop("div1"<span>);
</span><span>19</span> 
<span>20</span> <span>$s</span>->start("div2"<span>);
</span><span>21</span> <span>function</span> unique_rand(<span>$min</span>, <span>$max</span>, <span>$num</span><span>)
</span><span>22</span> <span>{
</span><span>23</span>         <span>$count</span> = 0<span>;
</span><span>24</span>         <span>$return</span> = <span>array</span><span>();
</span><span>25</span>         <span>while</span> (<span>$count</span> $num<span>) {
</span><span>26</span>             <span>$return</span>[] = <span>mt_rand</span>(<span>$min</span>, <span>$max</span><span>);
</span><span>27</span>             <span>$return</span> = <span>array_flip</span>(<span>array_flip</span>(<span>$return</span><span>));
</span><span>28</span>             <span>$count</span> = <span>count</span>(<span>$return</span><span>);
</span><span>29</span> <span>        }
</span><span>30</span>         <span>shuffle</span>(<span>$return</span><span>);
</span><span>31</span>         <span>return</span> <span>$return</span><span>;
</span><span>32</span> <span>}
</span><span>33</span> 
<span>34</span>     <span>$arr</span> = unique_rand(1, 1000000, 10000<span>);
</span><span>35</span>     <span>$result</span> = ''<span>;
</span><span>36</span>     <span>for</span>(<span>$i</span>=0; <span>$i</span> count(<span>$arr</span>);<span>$i</span>++<span>)
</span><span>37</span> <span>    {
</span><span>38</span>         <span>$result</span> = <span>$arr</span>[<span>$i</span><span>];
</span><span>39</span>         <span>echo</span> <span>$result</span>."<br>"<span>;
</span><span>40</span> <span>    }
</span><span>41</span>     <span>$s</span>->stop("div2"<span>);
</span><span>42</span> 
<span>43</span> 
<span>44</span> <span>//</span><span>输出时间</span>
<span>45</span> <span>echo</span> "div 1 Duration: " . <span>$s</span>->getDuration("div1") . " seconds.<br>"<span>;
</span><span>46</span> <span>echo</span> "div 2 Duration: " . <span>$s</span>->getDuration("div2") . " seconds.<br>"<span>;
</span><span>47</span> ?>
登录后复制

输出结果为:

<span>1</span> <span>前面省略………………
</span><span>2</span> div 1 Duration: 0.6050 seconds.
<span>3</span> div 2 Duration: 17.4260 seconds.
登录后复制

结论:对于第一种方法输出一个数据的时间,跟大数的数字时间差不多。但是第二个时间显然耗费得要离谱。达到了17.5秒。

 

总结:

1.翻翻法对于选少量数据好用,大量数据就会比较吃力。

 

本站声明
本文内容由网友自发贡献,版权归原作者所有,本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容,请联系admin@php.cn

热AI工具

Undresser.AI Undress

Undresser.AI Undress

人工智能驱动的应用程序,用于创建逼真的裸体照片

AI Clothes Remover

AI Clothes Remover

用于从照片中去除衣服的在线人工智能工具。

Undress AI Tool

Undress AI Tool

免费脱衣服图片

Clothoff.io

Clothoff.io

AI脱衣机

AI Hentai Generator

AI Hentai Generator

免费生成ai无尽的。

热门文章

R.E.P.O.能量晶体解释及其做什么(黄色晶体)
2 周前 By 尊渡假赌尊渡假赌尊渡假赌
仓库:如何复兴队友
4 周前 By 尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island冒险:如何获得巨型种子
3 周前 By 尊渡假赌尊渡假赌尊渡假赌

热工具

记事本++7.3.1

记事本++7.3.1

好用且免费的代码编辑器

SublimeText3汉化版

SublimeText3汉化版

中文版,非常好用

禅工作室 13.0.1

禅工作室 13.0.1

功能强大的PHP集成开发环境

Dreamweaver CS6

Dreamweaver CS6

视觉化网页开发工具

SublimeText3 Mac版

SublimeText3 Mac版

神级代码编辑软件(SublimeText3)

CakePHP 项目配置 CakePHP 项目配置 Sep 10, 2024 pm 05:25 PM

在本章中,我们将了解CakePHP中的环境变量、常规配置、数据库配置和电子邮件配置。

适用于 Ubuntu 和 Debian 的 PHP 8.4 安装和升级指南 适用于 Ubuntu 和 Debian 的 PHP 8.4 安装和升级指南 Dec 24, 2024 pm 04:42 PM

PHP 8.4 带来了多项新功能、安全性改进和性能改进,同时弃用和删除了大量功能。 本指南介绍了如何在 Ubuntu、Debian 或其衍生版本上安装 PHP 8.4 或升级到 PHP 8.4

CakePHP 日期和时间 CakePHP 日期和时间 Sep 10, 2024 pm 05:27 PM

为了在 cakephp4 中处理日期和时间,我们将使用可用的 FrozenTime 类。

CakePHP 文件上传 CakePHP 文件上传 Sep 10, 2024 pm 05:27 PM

为了进行文件上传,我们将使用表单助手。这是文件上传的示例。

CakePHP 路由 CakePHP 路由 Sep 10, 2024 pm 05:25 PM

在本章中,我们将学习以下与路由相关的主题?

讨论 CakePHP 讨论 CakePHP Sep 10, 2024 pm 05:28 PM

CakePHP 是 PHP 的开源框架。它的目的是使应用程序的开发、部署和维护变得更加容易。 CakePHP 基于类似 MVC 的架构,功能强大且易于掌握。模型、视图和控制器 gu

如何设置 Visual Studio Code (VS Code) 进行 PHP 开发 如何设置 Visual Studio Code (VS Code) 进行 PHP 开发 Dec 20, 2024 am 11:31 AM

Visual Studio Code,也称为 VS Code,是一个免费的源代码编辑器 - 或集成开发环境 (IDE) - 可用于所有主要操作系统。 VS Code 拥有针对多种编程语言的大量扩展,可以轻松编写

CakePHP 创建验证器 CakePHP 创建验证器 Sep 10, 2024 pm 05:26 PM

可以通过在控制器中添加以下两行来创建验证器。

See all articles