﻿<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:trackback="http://madskills.com/public/xml/rss/module/trackback/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/"><channel><title>C++博客-It Smils-随笔分类-algorithm</title><link>http://www.cppblog.com/ronliu/category/8751.html</link><description>思绪的自留地</description><language>zh-cn</language><lastBuildDate>Fri, 07 Nov 2008 13:11:13 GMT</lastBuildDate><pubDate>Fri, 07 Nov 2008 13:11:13 GMT</pubDate><ttl>60</ttl><item><title>战士取枪中的概率问题</title><link>http://www.cppblog.com/ronliu/archive/2008/10/23/64883.html</link><dc:creator>ronliu</dc:creator><author>ronliu</author><pubDate>Thu, 23 Oct 2008 14:09:00 GMT</pubDate><guid>http://www.cppblog.com/ronliu/archive/2008/10/23/64883.html</guid><wfw:comment>http://www.cppblog.com/ronliu/comments/64883.html</wfw:comment><comments>http://www.cppblog.com/ronliu/archive/2008/10/23/64883.html#Feedback</comments><slash:comments>0</slash:comments><wfw:commentRss>http://www.cppblog.com/ronliu/comments/commentRss/64883.html</wfw:commentRss><trackback:ping>http://www.cppblog.com/ronliu/services/trackbacks/64883.html</trackback:ping><description><![CDATA[6个战士，每个战士有他们自己的枪，6把枪摆在一起，6名战士依次取枪，问最后6名战士每人手中的枪都不是他们自己的概率。<br>1. 取枪的总可能性为6！<br>2. 第n个人取枪后，出现的可能性为f(n),则f(n) = (n-1)*(f(n-1) + f(n - 2))。<br>3. f(6)/6!<br><br>第一个战士拿枪，有两种可能，拿到的是第二个人的枪，以及拿到的不是第二个人的枪，导致f(n-2)和f(n-1)两种可能性。<br><br> <img src ="http://www.cppblog.com/ronliu/aggbug/64883.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://www.cppblog.com/ronliu/" target="_blank">ronliu</a> 2008-10-23 22:09 <a href="http://www.cppblog.com/ronliu/archive/2008/10/23/64883.html#Feedback" target="_blank" style="text-decoration:none;">发表评论</a></div>]]></description></item></channel></rss>