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<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<title><![CDATA[Joe's blog]]></title>
<subtitle><![CDATA[A pseudo coder!]]></subtitle>
<link href="/atom.xml" rel="self"/>
<link href="http://neverjoe.com/"/>
<updated>2015-09-22T06:24:30.029Z</updated>
<id>http://neverjoe.com/</id>
<author>
<name><![CDATA[Joe]]></name>
<email><![CDATA[tq0317@gmail.com]]></email>
</author>
<generator uri="http://zespia.tw/hexo/">Hexo</generator>
<entry>
<title><![CDATA[impala-sql入门]]></title>
<link href="http://neverjoe.com/2015/09/12/impala-sql%E5%85%A5%E9%97%A8/"/>
<id>http://neverjoe.com/2015/09/12/impala-sql入门/</id>
<published>2015-09-12T01:51:28.000Z</published>
<updated>2015-09-13T12:27:53.000Z</updated>
<content type="html"><![CDATA[<h2 id="引子">引子</h2>
<p>对比下Unix commands:<br></p>
<ul>
<li>CREATE DATABASE = mkdir</li>
<li>CREATE TABLE = mkdir</li>
<li>CREATE … PARTITIONED BY = mkdir -p</li>
<li>CREATE EXTERNAL TABLE … location = ln -s</li>
<li>LOAD DATA INPATH = mv</li>
<li>ATER TABLE … ADD PARTITION = mkdir</li>
<li>USE DATABASE = cd</li>
<li>SELECT = grep, find, sed, awk, cut, perl, python…</li>
<li>INSERT = cp, tee, dd, grep, find, sed, awk, perl, python…</li>
<li>DROP DATABASE = rmdir</li>
<li>DROP TABLE = rm -r</li>
<li>SELECT COUNT(*) = wc -l, grep -c</li>
</ul>
<h2 id="实例">实例</h2>
<h3 id="从本地上传文件到HDFS">从本地上传文件到HDFS</h3>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div></pre></td><td class="code"><pre><div class="line"><span class="xml"></span><span class="variable">$cd</span><span class="xml"> </span><span class="variable">${IMPALA_HOME}</span><span class="xml"></span></div><div class="line"><span class="variable">$mkdir</span><span class="xml"> tests_tq && cd tests_tq</span></div><div class="line"><span class="variable">$cat</span><span class="xml"> > csv.txt</span></div><div class="line"><span class="number">1</span><span class="xml">,red,apple,</span><span class="number">4</span><span class="xml"></span></div><div class="line"><span class="number">2</span><span class="xml">,orange,orange,</span><span class="number">3</span><span class="xml"></span></div><div class="line"><span class="number">3</span><span class="xml">,yellow,banana,</span><span class="number">3</span><span class="xml"></span></div><div class="line"><span class="number">4</span><span class="xml">,green,apple,</span><span class="number">4</span><span class="xml"></span></div><div class="line"><span class="keyword">^D</span><span class="xml"></span></div><div class="line"><span class="variable">$cat</span><span class="xml"> > more_csv.txt</span></div><div class="line"><span class="number">5</span><span class="xml">,blue,bubblegum,</span><span class="number">0.5</span><span class="xml"></span></div><div class="line"><span class="number">6</span><span class="xml">,indigo,balcjberry,</span><span class="number">0.2</span><span class="xml"></span></div><div class="line"><span class="keyword">^D</span><span class="xml"></span></div><div class="line"><span class="variable">$hadoop</span><span class="xml"> fs -mkdir /test-warehouse/tests_tq</span></div><div class="line"><span class="variable">$hadoop</span><span class="xml"> fs -put *.txt /test-warehouse/tests_tq</span></div></pre></td></tr></table></figure>
<h3 id="创建表格与导入数据">创建表格与导入数据</h3>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line"><span class="variable">$impala</span>-shell</div><div class="line">>create database food_colors;</div><div class="line">>use food_colors;</div><div class="line">>create table food_data</div><div class="line">>(</div><div class="line">>id <span class="keyword">int</span>, <span class="keyword">color</span> <span class="keyword">string</span>, food <span class="keyword">string</span>, weight <span class="keyword">float</span></div><div class="line">>)</div><div class="line">>row <span class="keyword">format</span> delimited fields terminated by ‘,’;</div><div class="line"><span class="variable">$load</span> data inpath ‘/test-warehouse/tests_tq’ into table food_data;</div><div class="line">><span class="keyword">select</span> food,<span class="keyword">color</span> as “possible Color” from food_data where food = ‘apple’;</div></pre></td></tr></table></figure>
<p>在create database后，impala会在相应的目录下生成database.db目录。<br><br>use database && create table后，impala会在相应database.db下生成表目录。<br><br>导入数据时，impala会把hdfs上的指定文件或者目录下所有文件移动到相应的表目录下，交由impala管理。<br><br>在建表时若使用external关键字，则数据原文件还是在location原地。<br><br>即建外表不需要导入数据，只需要在建表时指定路径关联即可。<br></p>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line"><span class="variable">$impala</span>-shell</div><div class="line">>create table xxx (xxxx)</div><div class="line">>location ‘/test-warehouse/tests_tq’;</div></pre></td></tr></table></figure>
<h2 id="常规操作">常规操作</h2>
<ul>
<li>CREATE (EXTERNAL) TABLE (LIKE, AS) (LOCATION)</li>
<li>SELECT</li>
<li>INSERT OVERWRITE (VALUES)</li>
<li>INSERT INTO (VALUES)</li>
<li>JOIN ON (USING)</li>
<li>AGGREGATION && GROUP BY</li>
<li>ORDER BY</li>
<li>PARTITIONED BY</li>
<li>limit 等</li>
</ul>
<h2 id="其他">其他</h2>
<p>一般impala-shell报错invalidata metadata时，则在操作impala支持不友好的数据类型，impala只能做查询操作，无法向其中写入数据。<br><br>而此时，需要使用hive进行相关操作，这样metadata变化，impala无法识别<br><br>如下操作，即可解决问题。</p>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line"><span class="variable">$impala</span>-shell</div><div class="line">><span class="keyword">refresh</span> table_name;</div></pre></td></tr></table></figure>
]]></content>
<summary type="html">
<![CDATA[<h2 id="引子">引子</h2>
<p>对比下Unix commands:<br></p>
<ul>
<li>CREATE DATABASE = mkdir</li>
<li>CREATE TABLE = mkdir</li>
<li>CREATE … PARTITIONE]]>
</summary>
<category term="impala" scheme="http://neverjoe.com/tags/impala/"/>
<category term="SQL-on-Hadoop" scheme="http://neverjoe.com/categories/SQL-on-Hadoop/"/>
</entry>
<entry>
<title><![CDATA[impala源码安装笔记]]></title>
<link href="http://neverjoe.com/2015/09/08/impala%E6%BA%90%E7%A0%81%E5%AE%89%E8%A3%85%E7%AC%94%E8%AE%B0/"/>
<id>http://neverjoe.com/2015/09/08/impala源码安装笔记/</id>
<published>2015-09-08T02:30:29.000Z</published>
<updated>2015-09-13T01:44:07.000Z</updated>
<content type="html"><![CDATA[<p>本文是采用git clone源码，部署单机cluster impala集群。目的是debug和围观impala源码，部署生产环境的请绕行。<br></p>
<h2 id="环境">环境</h2>
<ul>
<li><strong>ubuntu14.04.1</strong> 64bit, 16G Memory, Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz, 1TB disk</li>
<li>gcc/g++ 4.8.2</li>
</ul>
<h2 id="准备相关依赖">准备相关依赖</h2>
<h3 id="java">java</h3>
<p>安装java最新版即可。</p>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line">sudo <span class="built_in">add</span>-apt-repository <span class="keyword">pp</span><span class="variable">a:webupd8team</span>/java -<span class="keyword">y</span></div><div class="line">sudo apt-<span class="built_in">get</span> <span class="keyword">update</span> -<span class="keyword">y</span></div><div class="line"></div><div class="line"># Will have <span class="keyword">to</span> agree <span class="keyword">to</span> License</div><div class="line">sudo apt-<span class="built_in">get</span> install oracle-jdk7-installer -<span class="keyword">y</span></div></pre></td></tr></table></figure>
<h3 id="postgresql_&&_boost">postgresql && boost</h3>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">sudo apt-<span class="built_in">get</span> install git build-essential cmake bison flex pkg-config libsasl2-dev autoconf automake libtool maven subversion doxygen libbz2-dev zlib1g-dev <span class="keyword">python</span>-pip <span class="keyword">python</span>-setuptools <span class="keyword">python</span>-dev libssl-dev libboost-<span class="keyword">all</span>-dev postgresql liblzo2-dev lzop -<span class="keyword">y</span></div><div class="line">sudo pip install allpairs pytest pytest-xdist paramiko texttable prettytable sqlparse psutil==<span class="number">0.7</span>.<span class="number">1</span> pywebhdfs gitpython jenkinsapi</div></pre></td></tr></table></figure>
<h4 id="配置postgresql">配置postgresql</h4>
<h5 id="postgresql认证">postgresql认证</h5>
<p>编辑 /etc/postgresql/*/main/pg_hba.conf 文件。由于源码中默认user为hiveuser，包括metastore在内的user均为hiveuser，password均为‘password’。<br><br>而’whoami’不是hiveuser则无法通过postgresql的验证，需要修改上述文件。<br></p>
<ul>
<li>修改前：<br># TYPE DATABASE USER ADDRESS METHOD<br>local all all peer</li>
<li>修改后：<br># TYPE DATABASE USER ADDRESS METHOD<br>local all all peer map=myHiveMap</li>
</ul>
<p>其中需要在/etc/postgresql/*/main/pg_ident.conf<br><br>文件最后加入一行 <br><br> myHivemap your’whoami’ hiveuser<br><br>重启postgresql<br></p>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="built_in">sudo</span> service postgresql restart</div></pre></td></tr></table></figure>
<h5 id="postgresql中为metastore建立用户">postgresql中为metastore建立用户</h5>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">sudo -u postgres psql postgres</div><div class="line">postgres=# <span class="operator"><span class="keyword">CREATE</span> ROLE hiveuser LOGIN <span class="keyword">PASSWORD</span> ‘<span class="keyword">password</span>’;</span></div><div class="line">postgres=# <span class="operator"><span class="keyword">ALTER</span> ROLE hiveuser <span class="keyword">WITH</span> CREATEDB;</span></div></pre></td></tr></table></figure>
<h4 id="boost库配置">boost库配置</h4>
<p>ubuntu中自带boost库，而impala需要用到相关扩展库。</p>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div></pre></td><td class="code"><pre><div class="line"><span class="built_in">cd</span> /usr/lib/x86_64-linux-gnu</div><div class="line"><span class="built_in">sudo</span> ln <span class="operator">-s</span> libboost_filesystem.so libboost_filesystem-mt.so</div><div class="line"><span class="built_in">sudo</span> ln <span class="operator">-s</span> libboost_filesystem.a libboost_filesystem-mt.a</div><div class="line"><span class="built_in">sudo</span> ln <span class="operator">-s</span> libboost_system.so libboost_system-mt.so</div><div class="line"><span class="built_in">sudo</span> ln <span class="operator">-s</span> libboost_system.a libboost_system-mt.a</div><div class="line"><span class="built_in">sudo</span> ln <span class="operator">-s</span> libboost_regex.so libboost_regex-mt.so</div><div class="line"><span class="built_in">sudo</span> ln <span class="operator">-s</span> libboost_regex.a libboost_regex-mt.a</div></pre></td></tr></table></figure>
<h3 id="llvm">llvm</h3>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line">wget <span class="symbol">http:</span>/<span class="regexp">/llvm.org/releases</span><span class="regexp">/3.3/llvm</span>-<span class="number">3.3</span>.src.tar.gz</div><div class="line">tar xvf llvm-<span class="number">3.3</span>.src.tar.gz</div><div class="line">cd llvm-<span class="number">3.3</span>.src/tools/</div><div class="line">svn co <span class="symbol">http:</span>/<span class="regexp">/llvm.org/svn</span><span class="regexp">/llvm-project/cfe</span><span class="regexp">/tags/</span><span class="constant">RELEASE_33</span>/final/ clang</div><div class="line">cd ../projects/</div><div class="line">svn co <span class="symbol">http:</span>/<span class="regexp">/llvm.org/svn</span><span class="regexp">/llvm-project/compiler</span>-rt/tags/<span class="constant">RELEASE_33</span>/final compiler-rt</div><div class="line">cd ..</div><div class="line">./configure --with-pic</div><div class="line">make -j4 <span class="constant">REQUIRES_RTTI</span>=<span class="number">1</span></div><div class="line">sudo make install</div></pre></td></tr></table></figure>
<h3 id="Maven_3">Maven 3</h3>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">wget <span class="symbol">http:</span>/<span class="regexp">/www.interior-dsgn.com/apache</span><span class="regexp">/maven/maven</span>-<span class="number">3</span>/<span class="number">3.0</span>.<span class="number">5</span>/binaries/apache-maven-<span class="number">3.0</span>.<span class="number">5</span>-bin.tar.gz</div><div class="line">tar xvf apache-maven-<span class="number">3.0</span>.<span class="number">5</span>-bin.tar.gz && sudo mv apache-maven-<span class="number">3.0</span>.<span class="number">5</span> /usr/local</div></pre></td></tr></table></figure>
<h3 id="bashrc">bashrc</h3>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">export</span> JAVA_HOME=/usr/lib/jvm/java-<span class="number">7</span>-oracle</div><div class="line"><span class="keyword">export</span> IMPALA_HOME=<path to Impala></div><div class="line"><span class="keyword">export</span> BOOST_LIBRARYDIR=/usr/lib/x86_64-linux-gnu</div><div class="line"><span class="keyword">export</span> LD_LIBRARY_PATH=/usr/lib/x86_64-linux-gnu</div><div class="line"><span class="keyword">export</span> LC_ALL=”en_US.UTF-<span class="number">8</span>”</div><div class="line"><span class="keyword">export</span> M2_HOME=/usr/local/apache-maven-<span class="number">3.0</span>.<span class="number">5</span></div><div class="line"><span class="keyword">export</span> M2=<span class="variable">$M2_HOME</span>/bin</div><div class="line"><span class="keyword">export</span> PATH=<span class="variable">$M2</span>:<span class="variable">$PATH</span></div></pre></td></tr></table></figure>
<h3 id="hdfs_domain_sockets">hdfs domain sockets</h3>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">sudo mkdir <span class="regexp">/var/</span>lib<span class="regexp">/hadoop-hdfs/</span></div><div class="line">sudo chown <user> <span class="regexp">/var/</span>lib<span class="regexp">/hadoop-hdfs/</span><<span class="regexp">/user></span></div></pre></td></tr></table></figure>
<h3 id="ssh_password-less_for_HBase">ssh password-less for HBase</h3>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line"><span class="input"><span class="prompt">ssh-keygen -t dsa</span></span></div><div class="line"># Do not type in any passkey. Just press enter.</div><div class="line">cat ~/.ssh/id_dsa.pub >> ~<span class="regexp">/.ssh/authorized</span>_keys</div></pre></td></tr></table></figure>
<hr>
<p>以上完成了源码安装的准备事项。<br></p>
<h2 id="源码编译">源码编译</h2>
<h3 id="下载源码">下载源码</h3>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">git clone http<span class="variable">s:</span>//github.<span class="keyword">com</span>/cloudera/Impala.git</div></pre></td></tr></table></figure>
<h3 id="检查编译环境变量">检查编译环境变量</h3>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line"><span class="built_in">cd</span> <span class="variable">${IMPALA_HOME}</span></div><div class="line"><span class="built_in">source</span> bin/impala-config.sh</div></pre></td></tr></table></figure>
<h3 id="格式化HIVE_Metastore_&&_HDFS_">格式化HIVE Metastore && HDFS </h3>
<p>第一次编译的时，需要清除编译环境和格式化Metastore和HDFS namenode.</p>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="variable">${IMPALA_HOME}</span>/buildall.sh -noclean -skiptests -build_shared_libs -<span class="keyword">format</span></div></pre></td></tr></table></figure>
<h3 id="编译">编译</h3>
<h4 id="整体编译">整体编译</h4>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="variable">${IMPALA_HOME}</span>/buildall.sh -skiptests -build_shared_libs</div></pre></td></tr></table></figure>
<h4 id="单独编译backend">单独编译backend</h4>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="variable">$.</span>{<span class="constant">IMPALA_HOME</span>}/bin/make_debug.sh [-notests] -build_shared_libs</div></pre></td></tr></table></figure>
<h4 id="单独编译frontend">单独编译frontend</h4>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="built_in">cd</span> <span class="variable">${IMPALA_HOME}</span>/fe && mvn clean package dependency:copy-dependencies -DskipTests=<span class="literal">true</span></div></pre></td></tr></table></figure>
<h3 id="测试伪分布集群">测试伪分布集群</h3>
<h4 id="启动impala的相关支持">启动impala的相关支持</h4>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="constant">${IMPALA_HOME}</span>/testdata/bin/run-<span class="literal">all</span>.sh</div></pre></td></tr></table></figure>
<p>相关日志在${IMPALA_HOME}/cluster_logs/中。</p>
<h4 id="启动impala">启动impala</h4>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="variable">${IMPALA_HOME}</span>/bin/start-impala-<span class="keyword">cluster</span>.py</div></pre></td></tr></table></figure>
<h4 id="测试impala">测试impala</h4>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line"><span class="variable">$cd</span> <span class="variable">${IMPALA_HOME}</span></div><div class="line"><span class="variable">$impala</span>-shell.sh -q”SELECT version()”</div></pre></td></tr></table></figure>
<p>如下显示，则一切正常。<br><br> Starting Impala Shell without Kerberos authentication<br> Connected to localhost:21000<br> Server version: impalad version 2.2.0-INTERNAL DEBUG (build 47c90e004aecb928a37b926080098d30b96b4330)<br> Query: select version()<br> +———————————————————————————————————————————-+<br> | version() |<br> +———————————————————————————————————————————-+<br> | impalad version 2.2.0-INTERNAL DEBUG (build 47c90e004aecb928a37b926080098d30b96b4330) |<br> | Built on Sun, Mar 22 15:22:57 PDT 2015 |<br> +———————————————————————————————————————————-+<br> Fetched 1 row(s) in 0.05s<br></p>
<p>最后可以在localhost:25000查看伪分布式集群信息。</p>
]]></content>
<summary type="html">
<![CDATA[<p>本文是采用git clone源码，部署单机cluster impala集群。目的是debug和围观impala源码，部署生产环境的请绕行。<br></p>
<h2 id="环境">环境</h2>
<ul>
<li><strong>ubuntu14.04.1</strong>]]>
</summary>
<category term="impala" scheme="http://neverjoe.com/tags/impala/"/>
<category term="SQL-on-Hadoop" scheme="http://neverjoe.com/categories/SQL-on-Hadoop/"/>
</entry>
<entry>
<title><![CDATA[棋盘覆盖问题]]></title>
<link href="http://neverjoe.com/2014/10/18/%E6%A3%8B%E7%9B%98%E8%A6%86%E7%9B%96%E9%97%AE%E9%A2%98/"/>
<id>http://neverjoe.com/2014/10/18/棋盘覆盖问题/</id>
<published>2014-10-18T08:33:51.000Z</published>
<updated>2014-10-22T15:17:32.000Z</updated>
<content type="html"><![CDATA[<p>最近交了算法课的一次作业，涉及到了棋盘覆盖问题．<br><br>一个非常经典的分治算法题目，值得回顾与总结！<br><br>具体题目可以直接百度到，下面说明一下我的解题过程．<br><br>由于老师让用分治解题，就直接套用分治的思想，将大棋盘划分为小棋盘，棋盘大小是2^k*2^k．不假思索，二分一下得到如下图的四个子棋盘<br><br><img src="http://neverjoe.qiniudn.com/chesscover1.jpg/neverjoe" alt="二分棋盘" title="二分棋盘"><br><br>划分后，于是问题来了！之前我们用分治解排序问题时，划分继续排序即可，不用处理，情形还是一致．但棋盘覆盖问题，在这点上不同了．<br>由于全盘上只有一个特殊方格不可以被覆盖，在划分后四个子棋盘中，必然出现有三个子棋盘没有特殊方格，从而不能将问题递归处理！<br><br>处理办法显然只有一个，那就是将这三个子棋盘中的一个方格覆盖掉，而且三个子棋盘中一共覆盖的三个方格恰好组成一个L型骨牌,这样问题就迎刃而解了．同时，递归处理后，普通方格可以在这个过程中都被覆盖掉．而满足覆盖分别来自三个子棋盘的三个方格并构成L型骨牌的方法很容易想到，只要L型骨牌的位置在四个子棋盘交汇处即可！<br>总结一下：</p>
<ol>
<li>将棋盘等分为四个子棋盘</li>
<li>判定各个子棋盘是否存在特殊方格．是，则直接继续递归．否，则将子棋盘中覆盖掉一个方格．这样没有特殊方格的三个子棋盘均被覆盖掉一个普通方格，并组成L型骨牌</li>
<li>对四个子棋盘继续划分，递归，直到子棋盘大小为1x1</li>
</ol>
<p>L型骨牌覆盖棋盘的示意图如下:<br><br>其中红色方格为特殊方格,黑色部分为L型骨牌填充后的情形<br><br><img src="http://neverjoe.qiniudn.com/chesscover2.jpg/neverjoe" alt=""><br></p>
<p>具体实现时，需要给出一个初始的原点方格位置，这样便于判定方位！如下图，约定棋盘的左上角方格位置为(br,bc)即(0,0).特殊方格的位置为(sr,sc).<br><br><img src="http://neverjoe.qiniudn.com/chesscover3.jpg/neverjoe" alt=""><br><br>下面是c++代码实现：</p>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div><div class="line">42</div><div class="line">43</div><div class="line">44</div><div class="line">45</div><div class="line">46</div><div class="line">47</div><div class="line">48</div><div class="line">49</div><div class="line">50</div><div class="line">51</div><div class="line">52</div><div class="line">53</div><div class="line">54</div><div class="line">55</div><div class="line">56</div><div class="line">57</div><div class="line">58</div><div class="line">59</div><div class="line">60</div><div class="line">61</div><div class="line">62</div><div class="line">63</div><div class="line">64</div><div class="line">65</div><div class="line">66</div><div class="line">67</div><div class="line">68</div><div class="line">69</div><div class="line">70</div><div class="line">71</div><div class="line">72</div><div class="line">73</div><div class="line">74</div><div class="line">75</div><div class="line">76</div><div class="line">77</div><div class="line">78</div><div class="line">79</div><div class="line">80</div></pre></td><td class="code"><pre><div class="line">#include<iostream></div><div class="line">using <span class="keyword">namespace</span> std;</div><div class="line"><span class="keyword">int</span> L=<span class="number">0</span>;<span class="comment">//全局数据</span></div><div class="line">const <span class="keyword">int</span> MAX=<span class="number">64</span>;<span class="comment">//默认最大棋盘</span></div><div class="line"><span class="keyword">int</span> chess_board[MAX][MAX]={};</div><div class="line"></div><div class="line"><span class="keyword">int</span> main()</div><div class="line">{</div><div class="line"> void chesscover(<span class="keyword">int</span> ,<span class="keyword">int</span> ,<span class="keyword">int</span> ,<span class="keyword">int</span> ,<span class="keyword">int</span>);</div><div class="line"> cout<<<span class="string">"please input the size of your chess board"</span><<endl;</div><div class="line"> <span class="keyword">int</span> SIZE;</div><div class="line"> cin>>SIZE;</div><div class="line"> <span class="keyword">int</span> BC=<span class="number">0</span>;</div><div class="line"> <span class="keyword">int</span> BR=<span class="number">0</span>;</div><div class="line"> cout<<<span class="string">"(0,0) stands for the grid of top left coner in your chess board"</span><<endl;</div><div class="line"> cout<<<span class="string">"please input the special grid of your chess board"</span><<endl;</div><div class="line"> <span class="keyword">int</span> SR;</div><div class="line"> <span class="keyword">int</span> SC;</div><div class="line"> cin>>SR;</div><div class="line"> cin>>SC;</div><div class="line"> chesscover(BR,BR,SR,SC,SIZE);</div><div class="line"> <span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">0</span>;i<SIZE;i++)</div><div class="line"> <span class="keyword">for</span>(<span class="keyword">int</span> j=<span class="number">0</span>;j<SIZE;j++)</div><div class="line"> {</div><div class="line"> cout<<<span class="string">" "</span><<chess_board[i][j];</div><div class="line"> <span class="keyword">if</span>(j==SIZE-<span class="number">1</span>)</div><div class="line"> cout<<endl;</div><div class="line"> }</div><div class="line">}</div><div class="line"><span class="comment">//row行</span></div><div class="line"><span class="comment">//col列</span></div><div class="line"><span class="comment">//(br,bc)初始化为(0,0),棋盘左上角方格</span></div><div class="line"><span class="comment">//给出的(sr,sc)特殊方格</span></div><div class="line"><span class="comment">//</span></div><div class="line"><span class="comment">//由上面两个方格确定棋盘的相对方位</span></div><div class="line"><span class="comment">//</span></div><div class="line"><span class="comment">//L,第L个L型骨牌</span></div><div class="line">void chesscover(<span class="keyword">int</span> br,<span class="keyword">int</span> bc,<span class="keyword">int</span> sr,<span class="keyword">int</span> sc,<span class="keyword">int</span> <span class="keyword">size</span>)</div><div class="line">{</div><div class="line"> <span class="keyword">if</span>(<span class="keyword">size</span>==<span class="number">1</span>)</div><div class="line"> <span class="keyword">return</span>;</div><div class="line"> <span class="keyword">int</span> tmp=++L;<span class="comment">//每次进入三个else,一个if</span></div><div class="line"> <span class="keyword">size</span>/=<span class="number">2</span>;</div><div class="line"> <span class="comment">//特殊方格在左上子棋盘</span></div><div class="line"> <span class="keyword">if</span>(sr<<span class="keyword">size</span>+br&&sc<<span class="keyword">size</span>+bc)</div><div class="line"> chesscover(br,bc,sr,sc,<span class="keyword">size</span>);</div><div class="line"> <span class="keyword">else</span></div><div class="line"> {</div><div class="line"> <span class="comment">//覆盖左上子棋盘右下角的一个方格，继续递归处理该子棋盘</span></div><div class="line"> chess_board[<span class="keyword">size</span>+br-<span class="number">1</span>][<span class="keyword">size</span>+bc-<span class="number">1</span>]=tmp;</div><div class="line"> chesscover(br,bc,<span class="keyword">size</span>+br-<span class="number">1</span>,<span class="keyword">size</span>+bc-<span class="number">1</span>,<span class="keyword">size</span>);</div><div class="line"> }</div><div class="line"> <span class="comment">//特殊方格在左下子棋盘</span></div><div class="line"> <span class="keyword">if</span>(sr>=<span class="keyword">size</span>+br&&sc<<span class="keyword">size</span>+bc)</div><div class="line"> chesscover(br+<span class="keyword">size</span>,bc,sr,sc,<span class="keyword">size</span>);</div><div class="line"> <span class="keyword">else</span></div><div class="line"> {</div><div class="line"> <span class="comment">//覆盖左下子棋盘右上角的一个方格，继续递归处理该子棋盘</span></div><div class="line"> chess_board[<span class="keyword">size</span>+br][<span class="keyword">size</span>+bc-<span class="number">1</span>]=tmp;</div><div class="line"> chesscover(br+<span class="keyword">size</span>,bc,<span class="keyword">size</span>+br,<span class="keyword">size</span>+bc-<span class="number">1</span>,<span class="keyword">size</span>);</div><div class="line"> }</div><div class="line"> <span class="comment">//特殊方格在右上子棋盘</span></div><div class="line"> <span class="keyword">if</span>(sr<<span class="keyword">size</span>+br&&sc>=<span class="keyword">size</span>+bc)</div><div class="line"> chesscover(br,bc+<span class="keyword">size</span>,sr,sc,<span class="keyword">size</span>);</div><div class="line"> <span class="keyword">else</span></div><div class="line"> {</div><div class="line"> <span class="comment">//覆盖右上子棋盘左下角的一个方格，继续递归处理该子棋盘</span></div><div class="line"> chess_board[<span class="keyword">size</span>+br-<span class="number">1</span>][<span class="keyword">size</span>+bc]=tmp;</div><div class="line"> chesscover(br,bc+<span class="keyword">size</span>,<span class="keyword">size</span>+br-<span class="number">1</span>,<span class="keyword">size</span>+bc,<span class="keyword">size</span>);</div><div class="line"> }</div><div class="line"> <span class="comment">//特殊方格在右下子棋盘</span></div><div class="line"> <span class="keyword">if</span>(sr>=<span class="keyword">size</span>+br&&sc>=<span class="keyword">size</span>+bc)</div><div class="line"> chesscover(br+<span class="keyword">size</span>,bc+<span class="keyword">size</span>,sr,sc,<span class="keyword">size</span>);</div><div class="line"> <span class="keyword">else</span></div><div class="line"> {</div><div class="line"> <span class="comment">//覆盖右下子棋盘左上角的一个方格，继续递归处理该子棋盘</span></div><div class="line"> chess_board[<span class="keyword">size</span>+br][<span class="keyword">size</span>+bc]=tmp;</div><div class="line"> chesscover(<span class="keyword">size</span>+br,<span class="keyword">size</span>+bc,<span class="keyword">size</span>+br,<span class="keyword">size</span>+bc,<span class="keyword">size</span>);</div><div class="line"> }</div><div class="line">}</div></pre></td></tr></table></figure>
]]></content>
<summary type="html">
<![CDATA[<p>最近交了算法课的一次作业，涉及到了棋盘覆盖问题．<br><br>一个非常经典的分治算法题目，值得回顾与总结！<br><br>具体题目可以直接百度到，下面说明一下我的解题过程．<br><br>由于老师让用分治解题，就直接套用分治的思想，将大棋盘划分为小棋盘，棋盘大小是2^k*]]>
</summary>
<category term="算法与数据结构" scheme="http://neverjoe.com/tags/%E7%AE%97%E6%B3%95%E4%B8%8E%E6%95%B0%E6%8D%AE%E7%BB%93%E6%9E%84/"/>
<category term="学习笔记" scheme="http://neverjoe.com/categories/%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0/"/>
</entry>
<entry>
<title><![CDATA[使用七牛做图床]]></title>
<link href="http://neverjoe.com/2014/10/17/%E4%BD%BF%E7%94%A8%E4%B8%83%E7%89%9B%E5%81%9A%E5%9B%BE%E5%BA%8A/"/>
<id>http://neverjoe.com/2014/10/17/使用七牛做图床/</id>
<published>2014-10-17T04:02:49.000Z</published>
<updated>2014-10-17T09:44:17.000Z</updated>
<content type="html"><![CDATA[<p>准备写自主博客了，第三方imgbed看来是必备的．有了图床还是可以带来很多好处的，比如节省空间，便于编辑与管理，<br>加快网页访问速度等等<br><br>图床可以自己架设，前提是有主机有空间，国内外都行，不过考虑国内访问速度，在天朝弄个主机肯定会快的…<br>目前蓬勃发展云服务解决了很多问题，某些云服务商提供了图床服务，比如阿里云的oss，前面六个月免费，壕公司值得信赖！<br>最近火起来的<a href="https://portal.qiniu.com/signup?code=3lewblh9ozbrm" target="_blank" rel="external">七牛</a>也是相当不错的，免费用户还是有一些流量的．<br><br>进入七牛官网<a href="https://portal.qiniu.com/signup?code=3lewblh9ozbrm" target="_blank" rel="external">点我!</a> 注册激活后为体验用户，免费流量有限制，上传身份验证<br>(不得不说，对我来说这是一个梗.)后变为标准用户，就可以享受全部的免费流量了，10G对于小站来说还是不错的！在七牛建立一个公有空间后，上传图片即可支持外链！而且七牛还提供了一些其他非常好的服务，例如可以使用七牛的镜像存储对源站资源（文件/图片等）进行存储，可以对静态博客进行加速！<br>同时，七牛的数据处理功能，还可以处理图片，例如加水印，防盗链等等，说缺点的话．就是如果想绑定自己的域名需要备案，对于在狗爹上买域名的还是绕行吧，这么好的功能不能用，心塞阿！<br><br>配个七牛的内容管理界面，外链地址在右下角．．．<br><img src="http://neverjoe.qiniudn.com/qiniu.png" alt="使用七牛图床" title="使用七牛做图床"><br><br>最后总结一下:<br><br><a href="https://portal.qiniu.com/signup?code=3lewblh9ozbrm" target="_blank" rel="external">七牛</a>,不仅仅可以图床！</p>
]]></content>
<summary type="html">
<![CDATA[<p>准备写自主博客了，第三方imgbed看来是必备的．有了图床还是可以带来很多好处的，比如节省空间，便于编辑与管理，<br>加快网页访问速度等等<br><br>图床可以自己架设，前提是有主机有空间，国内外都行，不过考虑国内访问速度，在天朝弄个主机肯定会快的…<br>目前蓬勃发展]]>
</summary>
<category term="Hexo" scheme="http://neverjoe.com/tags/Hexo/"/>
<category term="学习笔记" scheme="http://neverjoe.com/categories/%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0/"/>
</entry>
<entry>
<title><![CDATA[github学生套件获取digitalocean vps优惠]]></title>
<link href="http://neverjoe.com/2014/10/14/%E5%88%A9%E7%94%A8github%E5%AD%A6%E7%94%9F%E5%A5%97%E4%BB%B6%E8%8E%B7%E5%8F%96digitalocean-vps%E4%BC%98%E6%83%A0/"/>
<id>http://neverjoe.com/2014/10/14/利用github学生套件获取digitalocean-vps优惠/</id>
<published>2014-10-13T16:01:22.000Z</published>
<updated>2014-11-19T08:25:37.000Z</updated>
<content type="html"><![CDATA[<p>最近github放出了对学生的大量优惠政策，下面就教大家怎么利用手上的edu邮箱获取do的100美元优惠码.</p>
<ol>
<li>有github账号的可以直接添加一个edu邮箱，没有的就用edu邮箱注册一个github账号．<a href="https://github.com/join" target="_blank" rel="external">注册猛戳这里</a></li>
<li>邮箱认证完毕有，<a href="https://education.github.com/pack" target="_blank" rel="external">继续猛戳这里</a>,点击get your pack,然后yes，接着进入信息填写界面，<br>选择你的edu邮箱申请student pack，简要填写后，就可以欢乐地提交申请了.github会通知你一个周内处理你的申请．</li>
<li>此时已经不用苦等，回到<a href="https://education.github.com/pack" target="_blank" rel="external">https://education.github.com/pack</a>, 猛击Get your pack，在下面的offers里面找到do,do的100优惠码到手一半了 </li>
<li>申请do的账号<a href="https://cloud.digitalocean.com/registrations/new" target="_blank" rel="external">猛戳!!!</a></li>
<li>申请验证完后，找到prom code处输入你的github提供的prom code．100美元到你的账号里面了！</li>
<li>do需要使用信用卡或者paypal,存入5美元激活账号！建议使用paypal，下面会说明原因．<br></li>
</ol>
<p>tips:</p>
<ol>
<li>在github student pack申请界面不要手贱进入requst a discount界面并提交申请!不然你的mac地址被锁定，github会默认你不是学生，直到你的请求被处理，<br>你的申请student pack界面一直会跳转到requst a discount界面！</li>
<li>github student pack有了或者添加了edu邮箱再申请,不要尝试上传照片等方法！</li>
<li>do会根据你信用卡绑定的do账号判别你是否有欺诈行为，被判定欺诈后果删do号!</li>
<li>一个do账号只能使用一次github student pack优惠码，lz亲身测…</li>
</ol>
]]></content>
<summary type="html">
<![CDATA[<p>最近github放出了对学生的大量优惠政策，下面就教大家怎么利用手上的edu邮箱获取do的100美元优惠码.</p>
<ol>
<li>有github账号的可以直接添加一个edu邮箱，没有的就用edu邮箱注册一个github账号．<a href="https://githu]]>
</summary>
<category term="vps" scheme="http://neverjoe.com/tags/vps/"/>
<category term="学习笔记" scheme="http://neverjoe.com/categories/%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0/"/>
</entry>
<entry>
<title><![CDATA[github+gitcafe+hexo搭建博客笔记]]></title>
<link href="http://neverjoe.com/2014/10/09/github-gitcafe-hexo%E6%90%AD%E5%BB%BA%E5%8D%9A%E5%AE%A2%E7%AC%94%E8%AE%B0/"/>
<id>http://neverjoe.com/2014/10/09/github-gitcafe-hexo搭建博客笔记/</id>
<published>2014-10-09T12:27:16.000Z</published>
<updated>2015-09-08T02:28:42.000Z</updated>
<content type="html"><![CDATA[<h2 id="github与gitcafe_rsa公钥">github与gitcafe rsa公钥</h2>
<p>按照<a href="https://help.github.com/articles/generating-ssh-keys/" target="_blank" rel="external">官方的文档</a>，生成rsa公钥，可以同时给github与gitcafe(需要账号信息一致）使用.<br><br>使用git提交时可能会出现Error: Permission denied (publickey)错误，但使用’’’ssh -vT git@github.com’’’时可能是因为生成ssh rsa时没有使用sudo，而使用git时若使用sudo了，则调用/root/下的rsa公钥.<br>解决方案:使用sudo生成rsa公钥!详解可以参考<a href="https://help.github.com/articles/error-permission-denied-publickey/" target="_blank" rel="external">官网文档</a><br></p>
<h2 id="github与gitcafe_pages使用">github与gitcafe pages使用</h2>
<p>把博客部署到github与gitcafe上这样就免去了购置vps的费用！<br><br>github与gitcafe部署上略有差别</p>
<ol>
<li>github上建立一个yourid.github.com的repo,而gitcafe为yourid.</li>
<li>branch没有现在，而gitcafe上必须为gitcafe-pages</li>
<li>gitcafe自定义域名的方式绑定域名，而github需要一个CNAME文件．同时gitcafe还支持多域名绑定.<br></li>
</ol>
<p>下面是gitcafe部署方法:<br></p>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line">cd yourid/pages</div><div class="line">git init</div><div class="line">git <span class="keyword">add</span> .</div><div class="line">git remote <span class="keyword">add</span> origin git@gitcafe.com:yourid/yourid.git</div><div class="line">git checkout -b gitcafe-pages</div><div class="line">git <span class="keyword">push</span> origin gitcafe-pages</div></pre></td></tr></table></figure>
<h2 id="Hexo_使用">Hexo 使用</h2>
<ol>
<li>多次渲染生成静态博客时，使用</li>
</ol>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="title">hexo</span> clean</div></pre></td></tr></table></figure>
<ol>
<li>出现提交问题时，使用</li>
</ol>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="title">rm</span> -rf .deploy/</div></pre></td></tr></table></figure>
<ol>
<li>使用复合命令</li>
</ol>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line"><span class="comment">hexo</span> <span class="comment">g</span> <span class="literal">-</span><span class="literal">-</span><span class="comment">d</span></div><div class="line"><span class="comment">hexo</span> <span class="comment">s</span> <span class="literal">-</span><span class="literal">-</span><span class="comment">g</span></div></pre></td></tr></table></figure>
<h2 id="域名及dns">域名及dns</h2>
<p>域名:</p>
<ol>
<li>上<a href="www.godaddy.com">godaddy</a>买域名</li>
<li>在狗爹上只是买了域名服务，想加速国内访问，还得弄个国内的dns服务．我用的<a href="https://yunjiasu.baidu.com" target="_blank" rel="external">百度云加速</a> </li>
<li>让搜索引擎发现你的博客-<a href="http://zhanzhang.baidu.com/sitesubmit/index" target="_blank" rel="external">baidu网址提交</a>,<a href="https://www.google.com/webmasters/tools/submit-url?pli=1" target="_blank" rel="external">google网址提交</a></li>
<li>图床，必须使用<a href="https://portal.qiniu.com/signup?code=3lewblh9ozbrm" target="_blank" rel="external">七牛</a>.免费10G</li>
</ol>
<p>dns设置建议:</p>
<ol>
<li>默认设置为gitcafe</li>
<li>国外设置为github</li>
<li>添加一些单独的运营商线路加速访问.</li>
</ol>
]]></content>
<summary type="html">
<![CDATA[<h2 id="github与gitcafe_rsa公钥">github与gitcafe rsa公钥</h2>
<p>按照<a href="https://help.github.com/articles/generating-ssh-keys/" target="_blank"]]>
</summary>
<category term="Hexo" scheme="http://neverjoe.com/tags/Hexo/"/>
<category term="学习笔记" scheme="http://neverjoe.com/categories/%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0/"/>
</entry>
<entry>
<title><![CDATA[my-markdown-syntax]]></title>
<link href="http://neverjoe.com/2014/10/01/my-markdown-syntax/"/>
<id>http://neverjoe.com/2014/10/01/my-markdown-syntax/</id>
<published>2014-09-30T19:17:29.000Z</published>
<updated>2015-03-10T18:40:34.000Z</updated>
<content type="html"><![CDATA[<h2 id="二级标题">二级标题</h2>
<p>最多支持６级标题！由#数量决定<br></p>
<h2 id="段落与换行">段落与换行</h2>
<p>一个空格以上加一个换行符就换行了哦！<br>你看我又换行了!<br>hello kitty!<br><br>使用html< br/>标签实现换行</p>
<h2 id="文本强调">文本强调</h2>
<p><em>斜体字</em>由下划线＿或者＊完成<br><br><strong>粗体字</strong><br><br><strong>粗体字</strong><br><br><strong><em>粗斜体</em></strong><br></p>
<h2 id="list_列表">list 列表</h2>
<ul>
<li>这是一个无序列表,+,-,*均支持！<br></li>
</ul>
<ul>
<li>使用-</li>
</ul>
<ul>
<li>使用+<br></li>
</ul>
<ol>
<li>这是一个有序列表</li>
<li>neverjoe.com </li>
</ol>
<ul>
<li>使用＋or -实现有序列表的增加</li>
</ul>
<ul>
<li>-同样可以增加<br></li>
</ul>
<p>不同列表之间需要换行后再空一行(再enter下)实现!<br><br>有时在文章开头需要用反斜杠转义屏蔽列表的出现如下：<br><br>2013.年度目标是．．．</p>
<h2 id="link_链接">link 链接</h2>
<h3 id="网站">网站</h3>
<p>内联方式:<br><br>使用一个[链接注释]与一个(<a href="http://example.com/" target="_blank" rel="external">http://example.com/</a>) 连在一起可以做出一个链接！<br>This is a <a href="https://github.com/neverjoe/" target="_blank" rel="external">fork me</a>.<br><a href="http://gitcafe.com/neverjoe/" target="_blank" rel="external">fork me</a>.<br><a href="http://neverjoe.com" target="_blank" rel="external">http://neverjoe.com</a> 默认识别为链接！<br><br>引用方式:<br><br>I want to go <a href="http://www.google.com/" title="google" target="_blank" rel="external">google</a> and <a href="http://www.baidu.com/" title="baidu" target="_blank" rel="external">baidu</a> to search something!</p>
<h3 id="邮箱">邮箱</h3>
<p><a href="mailto:tq0317@gmail.com">tq0317@gmail.com</a></p>
<h3 id="图片">图片</h3>
<p>内联方式:<br><br><img src="http://www.laboiteverte.fr/wp-content/uploads/2011/04/grille-point-croix-couture-geek-film-04.jpg" alt="图1" title="geekstyle"><br>引用方式:<br><br><img src="http://www.laboiteverte.fr/wp-content/uploads/2011/04/grille-point-croix-couture-geek-film-04.jpg" alt="图2" title="geekstyle"></p>
<p><img src="http://neverjoe.qiniudn.com/img1.png" alt="图3" title="qiniu"></p>
<h2 id="代码高亮">代码高亮</h2>
<p>使用缩进可以自动转换为代码块！下面是c++代码:</p>
<pre><code><span class="preprocessor">#<span class="keyword">include</span><iostream></span>
<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="built_in">std</span>;
<span class="keyword">int</span> main()
{
<span class="built_in">cout</span><<<span class="string">"hello world!"</span><<endl;
}
</code></pre><p>单独输入某些行代码时使用```</p>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">$ <span class="built_in">sudo</span> hexo s</div><div class="line">$ <span class="built_in">sudo</span> hexo g</div><div class="line">$ <span class="built_in">sudo</span> hexo d</div></pre></td></tr></table></figure>
<hr>
<p>使用２个以上的* or -连续或者分开的可以完成水平分割！</p>
<hr>
<h2 id="反斜杠转义\">反斜杠转义\</h2>
<p>Markdown 可以利用反斜杠来插入一些在语法中有其它意义的符号，例如：如果你想要用星号加在文字旁边的方式来做出强调效果，<br>你可以在星号的前面加上反斜杠：<br><br>\<em>literal asterisks\</em><br><br>Markdown 支持以下这些符号前面加上反斜杠来帮助插入普通的符号：<br><br>\反斜杠 `反引号 *星号 _下划线 {}花括号 []方括号 ()括弧 #井字号 +加号 -减号 .英文句 !感叹号</p>
<h2 id="脚注">脚注</h2>
<p>hello<a href="hi">^hello</a></p>
<h2 id="MathJax">MathJax</h2>
<p>You can render <em>LaTeX</em> mathematical expressions using <strong>MathJax</strong>, as on <a href="http://www.google.com/" title="google" target="_blank" rel="external">math.stackexchange.com</a>:</p>
<p>The <em>Gamma function</em> satisfying $\Gamma(n) = (n-1)!\quad\forall n\in\mathbb N$ is via the Euler integral</p>
<p>$$<br>\Gamma(z) = \int_0^\infty t^{z-1}e^{-t}dt\,.<br>$$</p>
<blockquote>
<p><strong>Tip:</strong> To make sure mathematical expressions are rendered properly on your website, include <strong>MathJax</strong> into your template:</p>
</blockquote>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="tag"><<span class="title">script</span> <span class="attribute">type</span>=<span class="value">"text/javascript"</span> <span class="attribute">src</span>=<span class="value">"https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS_HTML"</span>></span><span class="javascript"></span><span class="tag"></<span class="title">script</span>></span></div></pre></td></tr></table></figure>
<blockquote>
<p><strong>Note:</strong> You can find more information about <strong>LaTeX</strong> mathematical expressions <a href="http://meta.math.stackexchange.com/questions/5020/mathjax-basic-tutorial-and-quick-reference" target="_blank" rel="external">here</a>.</p>
</blockquote>
]]></content>
<summary type="html">
<![CDATA[<h2 id="二级标题">二级标题</h2>
<p>最多支持６级标题！由#数量决定<br></p>
<h2 id="段落与换行">段落与换行</h2>
<p>一个空格以上加一个换行符就换行了哦！<br>你看我又换行了!<br>hello kitty!<br><br>使用html]]>
</summary>
<category term="markdown" scheme="http://neverjoe.com/tags/markdown/"/>
<category term="学习笔记" scheme="http://neverjoe.com/categories/%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0/"/>
</entry>
</feed>