﻿<?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>BlogJava-gosyl-随笔分类-ACM</title><link>http://www.blogjava.net/gosyl/category/6776.html</link><description>Ｂｅ　ＹＯＵＲ　ｓｅＬＦ．</description><language>zh-cn</language><lastBuildDate>Tue, 27 Feb 2007 11:12:17 GMT</lastBuildDate><pubDate>Tue, 27 Feb 2007 11:12:17 GMT</pubDate><ttl>60</ttl><item><title>PROC:namenum    提交23次才通过....优化无止境</title><link>http://www.blogjava.net/gosyl/archive/2006/01/06/26880.html</link><dc:creator>gosyl</dc:creator><author>gosyl</author><pubDate>Fri, 06 Jan 2006 06:46:00 GMT</pubDate><guid>http://www.blogjava.net/gosyl/archive/2006/01/06/26880.html</guid><wfw:comment>http://www.blogjava.net/gosyl/comments/26880.html</wfw:comment><comments>http://www.blogjava.net/gosyl/archive/2006/01/06/26880.html#Feedback</comments><slash:comments>0</slash:comments><wfw:commentRss>http://www.blogjava.net/gosyl/comments/commentRss/26880.html</wfw:commentRss><trackback:ping>http://www.blogjava.net/gosyl/services/trackbacks/26880.html</trackback:ping><description><![CDATA[TASK: namenum<BR>LANG: JAVA<BR><BR>Compiling...<BR>Compile: OK<BR><BR>Executing...<BR>Test 1 OK [0.281333333333333 secs]<BR>Test 2 OK [0.339333333333333 secs]<BR>Test 3 OK [0.466 secs]<BR>Test 4 OK [0.276 secs]<BR>Test 5 OK [0.276666666666667 secs]<BR>Test 6 OK [0.276666666666667 secs]<BR>Test 7 OK [0.298 secs]<BR>Test 8 OK [0.404 secs]<BR>Test 9 OK [0.55 secs]<BR>Test 10 OK [0.900666666666667 secs]<BR>Test 11 OK [0.479333333333333 secs]<BR>Test 12 OK [0.908666666666667 secs]<BR>Test 13 OK [0.281333333333333 secs]<BR>Test 14 OK [0.278 secs]<BR>Test 15 OK [0.273333333333333 secs]<BR><BR>All tests OK.<BR>
<P>Your program ('namenum') produced all correct answers!&nbsp; This is your<BR>submission #23 for this problem.&nbsp; <B>Congratulations!</B><BR><BR><BR>关于效率问题的总结:<BR>1.递归与非递归:差别不大,前者test9用时1.6s,后者test9用时1.8s(我的非递归还慢些,汗,遂用递归的那个版本)<BR>2.关于类库中函数的效率:<BR>&nbsp;(1)使用Arraylist.add&gt;LinedList.add()&gt; Vector.add().<BR>&nbsp;(2)使用StringBuilder代替&nbsp;StringBuffer:后,效率提高不少,下图为证.<BR>TASK: namenum<BR>LANG: JAVA<BR><BR>Compiling...<BR>Compile: OK<BR><BR>Executing...<BR>sending data namenum<BR><BR>Test 1 OK [0.284666666666667 secs]<BR>Test 2 OK [0.338666666666667 secs]<BR>Test 3 OK [0.434666666666667 secs]<BR>Test 4 OK [0.274666666666667 secs]<BR>Test 5 OK [0.272666666666667 secs]<BR>Test 6 OK [0.276666666666667 secs]<BR>Test 7 OK [0.296666666666667 secs]<BR>Test 8 OK [0.394 secs]<BR>Test 9 OK [0.466 secs]<BR>Test 10 OK [0.658 secs]<BR>Test 11 OK [0.464 secs]<BR>Test 12 OK [0.660666666666667 secs]<BR>Test 13 OK [0.278666666666667 secs]<BR>Test 14 OK [0.277333333333333 secs]<BR>Test 15 OK [0.273333333333333 secs]<BR><BR>All tests&nbsp; OK.<BR></P>
<P>Your program ('namenum') produced all correct answers!&nbsp; This is your<BR>submission #24 for this problem.&nbsp; <B>Congratulations!<BR></B><BR>(3)瓶颈:下面的语句块在多次执行后表现出极低的性能<BR>&nbsp;&nbsp;&nbsp;{<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; StringBuffer name;<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Vector.add(name.toString());<BR>&nbsp;&nbsp; }<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;如果改成Vector.add("hello");则问题得到解决,说明当参数是常量时,Vector.add()有较好的性能,但如果参数是变量,性能就不行了. </P><img src ="http://www.blogjava.net/gosyl/aggbug/26880.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://www.blogjava.net/gosyl/" target="_blank">gosyl</a> 2006-01-06 14:46 <a href="http://www.blogjava.net/gosyl/archive/2006/01/06/26880.html#Feedback" target="_blank" style="text-decoration:none;">发表评论</a></div>]]></description></item></channel></rss>