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<?xml version="1.0" encoding="utf-8"?>
<search>
<entry>
<title>独孤九剑「破刀式」</title>
<link href="/2019/05/05/du-gu-jiu-jian-po-dao-shi/"/>
<url>/2019/05/05/du-gu-jiu-jian-po-dao-shi/</url>
<content type="html"><![CDATA[]]></content>
<categories>
<category> 独孤九剑 </category>
</categories>
<tags>
<tag> 快速排序 </tag>
<tag> 堆排序 </tag>
<tag> 流求任意个数的中位数 </tag>
</tags>
</entry>
<entry>
<title>独孤九剑「破剑式」</title>
<link href="/2019/05/02/du-gu-jiu-jian-po-jian-shi/"/>
<url>/2019/05/02/du-gu-jiu-jian-po-jian-shi/</url>
<content type="html"><![CDATA[<h4 id="1-稳定性"><a href="#1-稳定性" class="headerlink" title="1. 稳定性"></a>1. 稳定性</h4><p> 稳定性就是排序前后，相同元素所在的相对位置不变。</p><p> 冒泡 插入 归并 ——–><strong>稳定</strong></p><p> 选择 快排 堆排 ——–><strong>不稳定</strong></p><h4 id="2-工业界的综合排序（简单说明）"><a href="#2-工业界的综合排序（简单说明）" class="headerlink" title="2. 工业界的综合排序（简单说明）"></a>2. 工业界的综合排序（简单说明）</h4><p> 基本数据类型：快排 （基本类型不需要稳定性）</p><p> 自定义类型（结构体，类）： 归并 （可能要按照多个标准来排序，所以需要）（在某些递归范围小于60直接插排）</p><p> 数组很短 （一般在60以下，O（N^2）劣势表现不出来，而且常数项极少）： 插排</p><h4 id="3-排序问题的补充"><a href="#3-排序问题的补充" class="headerlink" title="3. 排序问题的补充"></a>3. 排序问题的补充</h4><p> 1.归并排序额外空间复杂度可以变成O（1），但是非常难，可以用归并排序内部缓存法</p><p> 2.快排可以做到稳定性，但是非常难，可以收 “01 table sort”</p><h4 id="4-比较器"><a href="#4-比较器" class="headerlink" title="4. 比较器"></a>4. 比较器</h4><p> 在面向对象语言中，涉及到复杂数据类型的时候，比如一个类有多个属性，我们要根据这个类的某一个属性进行排序，这时候就要用比较器，告诉高级语言，我们要用哪个属性的升序还是降序排列。</p><p>以优先队列（底层实现：堆），TreeMap（底层红黑树）为例，代码如下：</p><pre class=" language-java"><code class="language-java"><span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>Comparator<span class="token punctuation">;</span><span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>PriorityQueue<span class="token punctuation">;</span><span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>TreeSet<span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> 简单的比较器<span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">class</span> <span class="token class-name">studentComparator</span> <span class="token keyword">implements</span> <span class="token class-name">Comparator</span><span class="token operator"><</span>Student<span class="token operator">></span><span class="token punctuation">{</span> <span class="token annotation punctuation">@Override</span> <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">compare</span><span class="token punctuation">(</span>Student o1<span class="token punctuation">,</span> Student o2<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> o1<span class="token punctuation">.</span>id<span class="token operator">-</span>o2<span class="token punctuation">.</span>id<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> Student student1 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">"zhangsan"</span><span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">12</span><span class="token punctuation">)</span><span class="token punctuation">;</span> Student student2 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">"lisi"</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">12</span><span class="token punctuation">)</span><span class="token punctuation">;</span> Student student3 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">"wangwu"</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> PriorityQueue<span class="token operator"><</span>Student<span class="token operator">></span> heap <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PriorityQueue</span><span class="token operator"><</span>Student<span class="token operator">></span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">studentComparator</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> heap<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>student1<span class="token punctuation">)</span><span class="token punctuation">;</span> heap<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>student2<span class="token punctuation">)</span><span class="token punctuation">;</span> heap<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>student3<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token operator">!</span>heap<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> Student poll <span class="token operator">=</span> heap<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>poll<span class="token punctuation">.</span>name <span class="token operator">+</span> <span class="token string">" "</span> <span class="token operator">+</span> poll<span class="token punctuation">.</span>id <span class="token operator">+</span> <span class="token string">" "</span> <span class="token operator">+</span> poll<span class="token punctuation">.</span>age<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> TreeSet<span class="token operator"><</span>Student<span class="token operator">></span> tree <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">TreeSet</span><span class="token operator"><</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">studentComparator</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment" spellcheck="true">//.....</span> <span class="token punctuation">}</span><span class="token punctuation">}</span></code></pre><h4 id="5-桶排序"><a href="#5-桶排序" class="headerlink" title="5. 桶排序"></a>5. 桶排序</h4><p> 不基于比较的排序，比如说我有一组数据，他的范围是0~60，那么我们可以用长度为60的数组，然后按照每个数据出现的个数给对应的位置自增。比如说 数据是7770011，7个数，创造一个长度为7的数组，然后7自增三次，因为7有三个，0位置自增两次，1自增2次，然后按照次序复原即可。这个桶是个大概念，只是一个容器而已，具体可以是链表，堆……</p><h4 id="6-桶排序的应用—-MaxGap"><a href="#6-桶排序的应用—-MaxGap" class="headerlink" title="6. 桶排序的应用—-MaxGap"></a>6. 桶排序的应用—-MaxGap</h4><p>例题和分析详细看代码</p><h5 id="有bug版本"><a href="#有bug版本" class="headerlink" title="有bug版本"></a>有bug版本</h5><pre class=" language-java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">bug</span>版本最大间隙MaxGap <span class="token punctuation">{</span> <span class="token comment" spellcheck="true">/** * 补充问题 * 给定一个数组， 求如果排序之后， 相邻两数的最大差值， 要求时 * 间复杂度O(N)， 且要求不能用非基于比较的排序。(就是桶排序基数排序计数排序之类的) * * @param */</span> <span class="token comment" spellcheck="true">//1. 把问题转化为N个数，放在N+1个桶里，保证最后一个和第一个里面都有数字，那么中间绝对有空桶，</span> <span class="token comment" spellcheck="true">//举个例子，现在有这么几个数 1 8 4 6 12，分成范围为0-2 3-5 6-8 9-11 12-14这N+1个桶</span> <span class="token comment" spellcheck="true">// 0-2 3-5 6-8 9-11 12-14</span> <span class="token comment" spellcheck="true">// 1 4 6 8 12</span> <span class="token comment" spellcheck="true">//然后这个最大的差值只可能在不同的桶中产生，而不是在于一个桶中产生，为什么呢？想象一个极端的例子，</span> <span class="token comment" spellcheck="true">//一个桶的容量是9，可以有10-19的桶，20-39的桶、</span> <span class="token comment" spellcheck="true">// 一个桶内部 最大值 9 最小值 0</span> <span class="token comment" spellcheck="true">// 两个桶 最大值 19 最小值 1</span> <span class="token comment" spellcheck="true">// 还有一点是老师举的例子：想象一个空桶两侧有非空桶，两个非空桶构成相邻序列，第一个非空桶的最大值与第二个非空桶的最小值</span> <span class="token comment" spellcheck="true">// 的差值肯定大于一个桶内部的最大差值。这点可以举个例子试试。这也就是我们构造空桶的好处。那么是不是所有的最大间隙都是在空桶两侧</span> <span class="token comment" spellcheck="true">// 产生呢？我们想象这样一个例子10-19中有19,20-29没有数，30-39中有30，40-49中有49那么差值最大的在后两个桶中产生，所以不一定</span> <span class="token comment" spellcheck="true">// 吗？错误！是一定的，这点左神说的可能有点问题，你要是分组的话，就会发现肯定在空桶左右最大！这点进过大量实验哈哈哈，比如</span> <span class="token comment" spellcheck="true">// 他所举的例子 19 30 49 可能在于 10-19 20-29 30-39 40-49 50-59这个分组上不是这样的，但实际上是这样分组的吗？显然不是的</span> <span class="token comment" spellcheck="true">// 分4组，每一组是（49-19）/4 = 7 所以分组为 19-26 27-34 35-42 43-50,所以肯定在空桶周围产生，不信我明天用代码实现看看</span> <span class="token comment" spellcheck="true">// 睡觉了 困死了 2019年5月3日23:40:31</span> <span class="token comment" spellcheck="true">// 2019年5月4日23:24:38我错了，写了代码测试了下，我的想法是错的。不是空桶周围的两个桶能得到MaxGap，有可能还是相邻的两个不为空的桶</span> <span class="token comment" spellcheck="true">// 之间的，例如 19 35 52 73</span> <span class="token comment" spellcheck="true">// 19-29 30-40 41-51 52-62 63-73</span> <span class="token comment" spellcheck="true">// 19 35 52 69</span> <span class="token comment" spellcheck="true">//</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> a<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">35</span><span class="token punctuation">,</span> <span class="token number">19</span><span class="token punctuation">,</span> <span class="token number">25</span><span class="token punctuation">,</span> <span class="token number">49</span><span class="token punctuation">}</span><span class="token punctuation">;</span> <span class="token keyword">int</span> max<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span>a<span class="token punctuation">.</span>length <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">int</span> min<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span>a<span class="token punctuation">.</span>length <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">int</span> maxNum <span class="token operator">=</span> Integer<span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span> <span class="token keyword">int</span> minNum <span class="token operator">=</span> Integer<span class="token punctuation">.</span>MAX_VALUE<span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> maxNum <span class="token operator">=</span> Math<span class="token punctuation">.</span><span class="token function">max</span><span class="token punctuation">(</span>maxNum<span class="token punctuation">,</span> a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span> minNum <span class="token operator">=</span> Math<span class="token punctuation">.</span><span class="token function">min</span><span class="token punctuation">(</span>minNum<span class="token punctuation">,</span> a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">boolean</span> isEmpty<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">boolean</span><span class="token punctuation">[</span>a<span class="token punctuation">.</span>length <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> isEmpty<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> isEmpty<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> pos <span class="token operator">=</span> <span class="token function">getPos</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">,</span> maxNum<span class="token punctuation">,</span> minNum<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment" spellcheck="true">//隶属于哪个桶</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>isEmpty<span class="token punctuation">[</span>pos<span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> max<span class="token punctuation">[</span>pos<span class="token punctuation">]</span> <span class="token operator">=</span> min<span class="token punctuation">[</span>pos<span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">;</span> isEmpty<span class="token punctuation">[</span>pos<span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token boolean">false</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span> max<span class="token punctuation">[</span>pos<span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">></span> max<span class="token punctuation">[</span>pos<span class="token punctuation">]</span> <span class="token operator">?</span> a<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">:</span> max<span class="token punctuation">[</span>pos<span class="token punctuation">]</span><span class="token punctuation">;</span> min<span class="token punctuation">[</span>pos<span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator"><</span> min<span class="token punctuation">[</span>pos<span class="token punctuation">]</span> <span class="token operator">?</span> a<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">:</span> min<span class="token punctuation">[</span>pos<span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">int</span> g_Max <span class="token operator">=</span> Integer<span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> count <span class="token operator">=</span> i<span class="token punctuation">;</span> <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>isEmpty<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token operator">!</span>isEmpty<span class="token punctuation">[</span>count<span class="token punctuation">]</span><span class="token punctuation">)</span> count<span class="token operator">--</span><span class="token punctuation">;</span> g_Max <span class="token operator">=</span> max<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">-</span> min<span class="token punctuation">[</span>count <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">]</span> <span class="token operator">></span> g_Max <span class="token operator">?</span> max<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">-</span> min<span class="token punctuation">[</span>count <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">]</span> <span class="token operator">:</span> g_Max<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>g_Max<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span></code></pre><h5 id="无bug版本"><a href="#无bug版本" class="headerlink" title="无bug版本"></a>无bug版本</h5><pre class=" language-java"><code class="language-java"><span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>Arrays<span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> 最大间隙MaxGap <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">int</span> <span class="token function">maxGap</span><span class="token punctuation">(</span><span class="token keyword">int</span> a<span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>a<span class="token punctuation">.</span>length <span class="token operator"><</span> <span class="token number">2</span> <span class="token operator">||</span> a <span class="token operator">==</span> null<span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">int</span> max <span class="token operator">=</span> Integer<span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span> <span class="token keyword">int</span> min <span class="token operator">=</span> Integer<span class="token punctuation">.</span>MAX_VALUE<span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> max <span class="token operator">=</span> Math<span class="token punctuation">.</span><span class="token function">max</span><span class="token punctuation">(</span>max<span class="token punctuation">,</span>a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span> min <span class="token operator">=</span> Math<span class="token punctuation">.</span><span class="token function">min</span><span class="token punctuation">(</span>min<span class="token punctuation">,</span>a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">if</span><span class="token punctuation">(</span>min <span class="token operator">==</span> max<span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">int</span> maxs<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span>a<span class="token punctuation">.</span>length<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">int</span> mins<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span>a<span class="token punctuation">.</span>length<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">boolean</span> hasNum<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">boolean</span><span class="token punctuation">[</span>a<span class="token punctuation">.</span>length<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> pos <span class="token operator">=</span> <span class="token function">getGap</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span>max<span class="token punctuation">,</span>min<span class="token punctuation">,</span>a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span> maxs<span class="token punctuation">[</span>pos<span class="token punctuation">]</span> <span class="token operator">=</span> hasNum<span class="token punctuation">[</span>pos<span class="token punctuation">]</span><span class="token operator">?</span>Math<span class="token punctuation">.</span><span class="token function">max</span><span class="token punctuation">(</span>maxs<span class="token punctuation">[</span>pos<span class="token punctuation">]</span><span class="token punctuation">,</span>a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token operator">:</span>a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">;</span> mins<span class="token punctuation">[</span>pos<span class="token punctuation">]</span> <span class="token operator">=</span> hasNum<span class="token punctuation">[</span>pos<span class="token punctuation">]</span><span class="token operator">?</span>Math<span class="token punctuation">.</span><span class="token function">min</span><span class="token punctuation">(</span>mins<span class="token punctuation">[</span>pos<span class="token punctuation">]</span><span class="token punctuation">,</span>a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token operator">:</span>a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">;</span> hasNum<span class="token punctuation">[</span>pos<span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment" spellcheck="true">//求Maxgap</span> <span class="token keyword">int</span> g_Max <span class="token operator">=</span> maxs<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>hasNum<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">{</span> temp <span class="token operator">=</span> Math<span class="token punctuation">.</span><span class="token function">max</span><span class="token punctuation">(</span>temp<span class="token punctuation">,</span>mins<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token operator">-</span>g_Max<span class="token punctuation">)</span><span class="token punctuation">;</span> g_Max <span class="token operator">=</span> maxs<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">int</span> <span class="token function">getGap</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a<span class="token punctuation">,</span> <span class="token keyword">int</span> max<span class="token punctuation">,</span> <span class="token keyword">int</span> min<span class="token punctuation">,</span> <span class="token keyword">int</span> num<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> <span class="token punctuation">(</span>num <span class="token operator">-</span> min<span class="token punctuation">)</span><span class="token operator">*</span>a<span class="token punctuation">.</span>length<span class="token operator">/</span><span class="token punctuation">(</span>max <span class="token operator">-</span> min<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment" spellcheck="true">// for test</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">int</span> <span class="token function">comparator</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> nums<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>nums <span class="token operator">==</span> null <span class="token operator">||</span> nums<span class="token punctuation">.</span>length <span class="token operator"><</span> <span class="token number">2</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> Arrays<span class="token punctuation">.</span><span class="token function">sort</span><span class="token punctuation">(</span>nums<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">int</span> gap <span class="token operator">=</span> Integer<span class="token punctuation">.</span>MIN_VALUE<span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span> i <span class="token operator"><</span> nums<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> gap <span class="token operator">=</span> Math<span class="token punctuation">.</span><span class="token function">max</span><span class="token punctuation">(</span>nums<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">-</span> nums<span class="token punctuation">[</span>i <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">,</span> gap<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> gap<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment" spellcheck="true">// for test</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">generateRandomArray</span><span class="token punctuation">(</span><span class="token keyword">int</span> maxSize<span class="token punctuation">,</span> <span class="token keyword">int</span> maxValue<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span> <span class="token punctuation">(</span><span class="token punctuation">(</span>maxSize <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">)</span> <span class="token operator">*</span> Math<span class="token punctuation">.</span><span class="token function">random</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> arr<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> arr<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span> <span class="token punctuation">(</span><span class="token punctuation">(</span>maxValue <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">)</span> <span class="token operator">*</span> Math<span class="token punctuation">.</span><span class="token function">random</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token operator">-</span> <span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span> <span class="token punctuation">(</span>maxValue <span class="token operator">*</span> Math<span class="token punctuation">.</span><span class="token function">random</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> arr<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment" spellcheck="true">// for test</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">copyArray</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>arr <span class="token operator">==</span> null<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> null<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> res <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span>arr<span class="token punctuation">.</span>length<span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> arr<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> res<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">=</span> arr<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> res<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token comment" spellcheck="true">// for test</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> testTime <span class="token operator">=</span> <span class="token number">500000</span><span class="token punctuation">;</span> <span class="token keyword">int</span> maxSize <span class="token operator">=</span> <span class="token number">100</span><span class="token punctuation">;</span> <span class="token keyword">int</span> maxValue <span class="token operator">=</span> <span class="token number">100</span><span class="token punctuation">;</span> <span class="token keyword">boolean</span> succeed <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> testTime<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr1 <span class="token operator">=</span> <span class="token function">generateRandomArray</span><span class="token punctuation">(</span>maxSize<span class="token punctuation">,</span> maxValue<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> arr2 <span class="token operator">=</span> <span class="token function">copyArray</span><span class="token punctuation">(</span>arr1<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">maxGap</span><span class="token punctuation">(</span>arr1<span class="token punctuation">)</span> <span class="token operator">!=</span> <span class="token function">comparator</span><span class="token punctuation">(</span>arr2<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> succeed <span class="token operator">=</span> <span class="token boolean">false</span><span class="token punctuation">;</span> <span class="token keyword">break</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>succeed <span class="token operator">?</span> <span class="token string">"Nice!"</span> <span class="token operator">:</span> <span class="token string">"Fucking fucked!"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span></code></pre><p>于2019年5月5日17:16:32 </p><p>Lucien</p><p>2019年5月6日20:23:14更新，还没完哈哈哈</p><h4 id="7-用数组结构实现队列和栈"><a href="#7-用数组结构实现队列和栈" class="headerlink" title="7. 用数组结构实现队列和栈"></a>7. 用数组结构实现队列和栈</h4><p>太简单了，直接贴代码。<strong>tip：用size可以控制大小，可以减少start和end的耦合性</strong></p><pre class=" language-java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">class</span> 栈和队列 <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">class</span> <span class="token class-name">stack</span><span class="token punctuation">{</span> <span class="token keyword">private</span> <span class="token keyword">int</span> arr<span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">private</span> <span class="token keyword">int</span> index<span class="token punctuation">;</span> <span class="token keyword">private</span> <span class="token function">stack</span><span class="token punctuation">(</span><span class="token keyword">int</span> initsize<span class="token punctuation">)</span> <span class="token keyword">throws</span> Exception <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>initsize <span class="token operator"><</span> <span class="token number">0</span><span class="token punctuation">)</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">Exception</span><span class="token punctuation">(</span><span class="token string">"初始化大学非负数"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> arr <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span>initsize<span class="token punctuation">]</span><span class="token punctuation">;</span> index <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">int</span> <span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> Exception <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>index <span class="token operator">==</span> <span class="token number">0</span><span class="token punctuation">)</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">Exception</span><span class="token punctuation">(</span><span class="token string">"已经没有元素了"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">return</span> arr<span class="token punctuation">[</span><span class="token operator">--</span>index<span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">int</span> <span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> Exception <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>index <span class="token operator">==</span> <span class="token number">0</span><span class="token punctuation">)</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">Exception</span><span class="token punctuation">(</span><span class="token string">"没有元素了哇"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">return</span> arr<span class="token punctuation">[</span>index<span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">push</span><span class="token punctuation">(</span><span class="token keyword">int</span> obj<span class="token punctuation">)</span> <span class="token keyword">throws</span> Exception <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>index <span class="token operator">==</span> arr<span class="token punctuation">.</span>length<span class="token punctuation">)</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">Exception</span><span class="token punctuation">(</span><span class="token string">"已经满了"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> arr<span class="token punctuation">[</span>index<span class="token operator">++</span><span class="token punctuation">]</span> <span class="token operator">=</span> obj<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">boolean</span> <span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">return</span> index<span class="token operator">==</span><span class="token number">0</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">class</span> <span class="token class-name">quene</span><span class="token punctuation">{</span> <span class="token keyword">private</span> <span class="token keyword">int</span> arr<span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">private</span> <span class="token keyword">int</span> start<span class="token punctuation">;</span> <span class="token keyword">private</span> <span class="token keyword">int</span> end<span class="token punctuation">;</span> <span class="token keyword">private</span> <span class="token keyword">int</span> size<span class="token punctuation">;</span> <span class="token keyword">private</span> <span class="token function">quene</span><span class="token punctuation">(</span><span class="token keyword">int</span> initsize<span class="token punctuation">)</span> <span class="token keyword">throws</span> Exception <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>initsize <span class="token operator"><</span> <span class="token number">0</span><span class="token punctuation">)</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">Exception</span><span class="token punctuation">(</span><span class="token string">"初始化大小不能为负数"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> arr <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span>initsize<span class="token punctuation">]</span><span class="token punctuation">;</span> size <span class="token operator">=</span> start <span class="token operator">=</span> end <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">push</span><span class="token punctuation">(</span><span class="token keyword">int</span> obj<span class="token punctuation">)</span> <span class="token keyword">throws</span> Exception <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>size <span class="token operator">==</span> arr<span class="token punctuation">.</span>length<span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">Exception</span><span class="token punctuation">(</span><span class="token string">"队列已经满了"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> arr<span class="token punctuation">[</span>end<span class="token punctuation">]</span> <span class="token operator">=</span> obj<span class="token punctuation">;</span> end <span class="token operator">=</span> end<span class="token operator">==</span>arr<span class="token punctuation">.</span>length<span class="token operator">-</span><span class="token number">1</span><span class="token operator">?</span><span class="token number">0</span><span class="token operator">:</span>end<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">;</span> size<span class="token operator">++</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">int</span> <span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> Exception <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>size <span class="token operator">==</span> <span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">Exception</span><span class="token punctuation">(</span><span class="token string">"没有元素了"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token operator">--</span>size<span class="token punctuation">;</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> arr<span class="token punctuation">[</span>start<span class="token punctuation">]</span><span class="token punctuation">;</span> start <span class="token operator">=</span> start <span class="token operator">==</span> arr<span class="token punctuation">.</span>length<span class="token operator">-</span><span class="token number">1</span><span class="token operator">?</span><span class="token number">0</span><span class="token operator">:</span>start<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">;</span> <span class="token keyword">return</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> Exception <span class="token punctuation">{</span> stack stack <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">stack</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> stack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> stack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> stack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token operator">!</span>stack<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>stack<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> stack<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> quene quene <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">quene</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> quene<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> quene<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">6</span><span class="token punctuation">)</span><span class="token punctuation">;</span> quene<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> quene<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> quene<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>quene<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>quene<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>quene<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> Queue<span class="token operator"><</span>Integer<span class="token operator">></span> integers <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayBlockingQueue</span><span class="token operator"><</span>Integer<span class="token operator">></span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">6</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token operator">!</span>integers<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>integers<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span><span class="token punctuation">}</span></code></pre><h4 id="8-求个栈的getmin的函数，要求为o-1-的复杂度"><a href="#8-求个栈的getmin的函数，要求为o-1-的复杂度" class="headerlink" title="8. 求个栈的getmin的函数，要求为o(1)的复杂度"></a>8. 求个栈的getmin的函数，要求为o(1)的复杂度</h4><p>这个邓公讲过，当时他讲的很绕，很复杂，但是左神一点就醒了，就是用双栈结构来做，具体代码如下：</p><h5 id="我自己先实现的，就是每次会清除掉原来栈的信息，最后可以又给原来的栈。"><a href="#我自己先实现的，就是每次会清除掉原来栈的信息，最后可以又给原来的栈。" class="headerlink" title="我自己先实现的，就是每次会清除掉原来栈的信息，最后可以又给原来的栈。"></a>我自己先实现的，就是每次会清除掉原来栈的信息，最后可以又给原来的栈。</h5><pre class=" language-java"><code class="language-java"> Stack<span class="token operator"><</span>Integer<span class="token operator">></span> integers <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Stack</span><span class="token operator"><</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">20</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">210</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> integers<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token function">getMin</span><span class="token punctuation">(</span>integers<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">int</span> <span class="token function">getMin</span><span class="token punctuation">(</span>Stack<span class="token operator"><</span>Integer<span class="token operator">></span> e<span class="token punctuation">)</span><span class="token punctuation">{</span> Stack<span class="token operator"><</span>Integer<span class="token operator">></span> Data <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Stack</span><span class="token operator"><</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token operator">!</span>e<span class="token punctuation">.</span><span class="token function">empty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> Data<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>e<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> Stack<span class="token operator"><</span>Integer<span class="token operator">></span> Min <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Stack</span><span class="token operator"><</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token operator">!</span>e<span class="token punctuation">.</span><span class="token function">empty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> e<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">if</span><span class="token punctuation">(</span>Min<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> Min<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>temp<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token keyword">else</span> <span class="token keyword">if</span><span class="token punctuation">(</span>temp <span class="token operator">></span> Min<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> Min<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>Min<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token keyword">else</span><span class="token punctuation">{</span> Min<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>temp<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> Min<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span></code></pre><h5 id="老师把这个结构看成一个对象，然后类似于装饰器来增加了新功能，我以为每次要是大于原来Min栈顶的话，都要添加push一次最小的元素，后来发现这个办法有点捞，左神这样想的，小于就添加，不让不添加，pop的时候，如果pop的这个元素是最小值，那么一定pop掉Min的元素，然后Min的下一个元素就是在当前的Data栈中最小的元素，想法奇特，小生佩服。"><a href="#老师把这个结构看成一个对象，然后类似于装饰器来增加了新功能，我以为每次要是大于原来Min栈顶的话，都要添加push一次最小的元素，后来发现这个办法有点捞，左神这样想的，小于就添加，不让不添加，pop的时候，如果pop的这个元素是最小值，那么一定pop掉Min的元素，然后Min的下一个元素就是在当前的Data栈中最小的元素，想法奇特，小生佩服。" class="headerlink" title="老师把这个结构看成一个对象，然后类似于装饰器来增加了新功能，我以为每次要是大于原来Min栈顶的话，都要添加push一次最小的元素，后来发现这个办法有点捞，左神这样想的，小于就添加，不让不添加，pop的时候，如果pop的这个元素是最小值，那么一定pop掉Min的元素，然后Min的下一个元素就是在当前的Data栈中最小的元素，想法奇特，小生佩服。"></a>老师把这个结构看成一个对象，然后类似于装饰器来增加了新功能，我以为每次要是大于原来Min栈顶的话，都要添加push一次最小的元素，后来发现这个办法有点捞，左神这样想的，小于就添加，不让不添加，pop的时候，如果pop的这个元素是最小值，那么一定pop掉Min的元素，然后Min的下一个元素就是在当前的Data栈中最小的元素，想法奇特，小生佩服。</h5><pre class=" language-java"><code class="language-java"> getMinStack getMinStack <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">getMinStack</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> getMinStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> getMinStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">)</span><span class="token punctuation">;</span> getMinStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> getMinStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">2000</span><span class="token punctuation">)</span><span class="token punctuation">;</span> getMinStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span> getMinStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">20</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>getMinStack<span class="token punctuation">.</span><span class="token function">getMin</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">class</span> <span class="token class-name">getMinStack</span><span class="token punctuation">{</span> <span class="token keyword">private</span> Stack<span class="token operator"><</span>Integer<span class="token operator">></span> Data<span class="token punctuation">;</span> <span class="token keyword">private</span> Stack<span class="token operator"><</span>Integer<span class="token operator">></span> Min<span class="token punctuation">;</span> <span class="token keyword">public</span> <span class="token function">getMinStack</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> Data <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Stack</span><span class="token operator"><</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> Min <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Stack</span><span class="token operator"><</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">push</span><span class="token punctuation">(</span><span class="token keyword">int</span> obj<span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>Min<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> Min<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>obj<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token keyword">else</span> <span class="token keyword">if</span><span class="token punctuation">(</span>obj <span class="token operator"><=</span> Min<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> Min<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>obj<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> Data<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>obj<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>Min<span class="token punctuation">.</span><span class="token function">empty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">RuntimeException</span> <span class="token punctuation">(</span><span class="token string">"已经没有元素了"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> Data<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">if</span><span class="token punctuation">(</span>temp <span class="token operator">==</span> Min<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> Min<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getMin</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>Min<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">RuntimeException</span><span class="token punctuation">(</span><span class="token string">"没有元素了"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> Min<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span></code></pre><h4 id="9-用队列结构实现栈"><a href="#9-用队列结构实现栈" class="headerlink" title="9. 用队列结构实现栈"></a>9. 用队列结构实现栈</h4><p>用的双向队列，有n个元素，要返回peek，要n-1个元素放入另外一个help队列中，然后返回这第n个元素，交换help和data的索引，也就是始终有一个空队列可以转化最后一个元素，从而达到实现栈的目的。</p><pre class=" language-java"><code class="language-java"><span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>LinkedList<span class="token punctuation">;</span><span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>Queue<span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> 双队列实现栈 <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">class</span> <span class="token class-name">twoQueneStack</span><span class="token operator"><</span>I <span class="token keyword">extends</span> <span class="token class-name">Number</span><span class="token operator">></span> <span class="token punctuation">{</span> <span class="token keyword">private</span> Queue<span class="token operator"><</span>Integer<span class="token operator">></span> data<span class="token punctuation">;</span> <span class="token keyword">private</span> Queue<span class="token operator"><</span>Integer<span class="token operator">></span> help<span class="token punctuation">;</span> <span class="token keyword">public</span> <span class="token function">twoQueneStack</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">this</span><span class="token punctuation">.</span>data <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">LinkedList</span><span class="token operator"><</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">this</span><span class="token punctuation">.</span>help <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">LinkedList</span><span class="token operator"><</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">push</span><span class="token punctuation">(</span><span class="token keyword">int</span> obj<span class="token punctuation">)</span><span class="token punctuation">{</span> data<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>obj<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>data<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">></span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">{</span> help<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>data<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> data<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> help<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>temp<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token function">swap</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">return</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>data<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">></span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">{</span> help<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>data<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> data<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token function">swap</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">return</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">swap</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> Queue<span class="token operator"><</span>Integer<span class="token operator">></span> temp <span class="token operator">=</span> data<span class="token punctuation">;</span> data <span class="token operator">=</span> help<span class="token punctuation">;</span> help <span class="token operator">=</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> twoQueneStack t <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">twoQueneStack</span><span class="token operator"><</span>Integer<span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> t<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> t<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> t<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> t<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">;</span> t<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>t<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> t<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> t<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>t<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span></code></pre><h4 id="10-双栈实现队列"><a href="#10-双栈实现队列" class="headerlink" title="10. 双栈实现队列"></a>10. 双栈实现队列</h4><p>一个push栈和一个pop栈，把push的所有东西压入pop，然后peek，pop即可。</p><pre class=" language-java"><code class="language-java"><span class="token keyword">import</span> java<span class="token punctuation">.</span>util<span class="token punctuation">.</span>Stack<span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">class</span> 双栈实现队列 <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">class</span> <span class="token class-name">twoStack</span><span class="token punctuation">{</span> <span class="token keyword">private</span> Stack<span class="token operator"><</span>Integer<span class="token operator">></span> stackpush<span class="token punctuation">;</span> <span class="token keyword">private</span> Stack<span class="token operator"><</span>Integer<span class="token operator">></span> stackpop<span class="token punctuation">;</span> <span class="token keyword">public</span> <span class="token function">twoStack</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> stackpop <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Stack</span><span class="token operator"><</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> stackpush <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Stack</span><span class="token operator"><</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">push</span><span class="token punctuation">(</span><span class="token keyword">int</span> obj<span class="token punctuation">)</span><span class="token punctuation">{</span> stackpush<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span>obj<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>stackpop<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">&&</span> stackpush<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">RuntimeException</span><span class="token punctuation">(</span><span class="token string">"队列为空"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token keyword">else</span> <span class="token keyword">if</span><span class="token punctuation">(</span>stackpop<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token operator">!</span>stackpush<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> stackpop<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span>stackpush<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> stackpop<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>stackpop<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">&&</span> stackpush<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">RuntimeException</span><span class="token punctuation">(</span><span class="token string">"队列为空"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token keyword">else</span> <span class="token keyword">if</span><span class="token punctuation">(</span>stackpop<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token operator">!</span>stackpush<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span> stackpop<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span>stackpush<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> stackpop<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> twoStack twoStack <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">twoStack</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> twoStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> twoStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">21</span><span class="token punctuation">)</span><span class="token punctuation">;</span> twoStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">13</span><span class="token punctuation">)</span><span class="token punctuation">;</span> twoStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">14</span><span class="token punctuation">)</span><span class="token punctuation">;</span> twoStack<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span><span class="token number">15</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>twoStack<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>twoStack<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>twoStack<span class="token punctuation">.</span><span class="token function">peek</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span></code></pre><p>感觉好痛苦啊！是我过于急功近利还是算法本来就是个慢过程，那些大佬学的好快啊！</p><p>Lucien</p><p>2019年5月6日23:16:39</p>]]></content>
<categories>
<category> 独孤九剑 </category>
</categories>
<tags>
<tag> 稳定性 </tag>
<tag> 工业界的综合排序 </tag>
<tag> 排序问题的补充 </tag>
<tag> 比较器 </tag>
<tag> 桶排序 </tag>
<tag> 桶排序的应用----MaxGap </tag>
<tag> 用数组结构实现队列和栈 </tag>
<tag> 求个栈的getmin的函数，要求为o(1)的复杂度 </tag>
<tag> 用队列结构实现栈 </tag>
<tag> 双栈实现队列 </tag>
</tags>
</entry>
<entry>
<title>独孤九剑「总决式」</title>
<link href="/2019/05/02/du-gu-jiu-jian-zong-qi-shi/"/>
<url>/2019/05/02/du-gu-jiu-jian-zong-qi-shi/</url>
<content type="html"><![CDATA[<h4 id="1-快速排序"><a href="#1-快速排序" class="headerlink" title="1. 快速排序"></a>1. 快速排序</h4><h5 id="1-1-快速排序的实质"><a href="#1-1-快速排序的实质" class="headerlink" title="1.1 快速排序的实质"></a>1.1 快速排序的实质</h5><p> 一般经典快速排序是这样的：首先拿一个num(就是即将排序的元素)，我们把小于num的元素放在左边，大于num的元素放在左边，如此循环下去，每一个元素都这样做，就拍好了序。</p><h5 id="1-2-快排的优化"><a href="#1-2-快排的优化" class="headerlink" title="1.2 快排的优化"></a>1.2 快排的优化</h5><p> 快排的优化主要是对于=num的部分进行优化，我们都知道一个数字可能在排序中出现的次数不止一次，可能有多次，这时候我们可以在原来快排的基础上加上一个==num的部分，这样就减少了次数，虽说时间复杂度不变都是O（N<em>logN），当然这是期望值。还有一点优化就是每一次拿到的num是随机抽取的，而不是第一个，第二个那样。比如说我们给一个有序的序列排序1 2 3 4 5 6 7，那么第一次拿1,小于1的部分不存在，剩下的都是大于1的，2也同理。这样次数就是n+n-1+n-2+….+1，复杂度就变成了o（N^2）,对于这样的问题，只要我们随机拿到初值num，对其求数学期望就会发现是O（N\</em>logN）。</p><h5 id="1-3-代码如下"><a href="#1-3-代码如下" class="headerlink" title="1.3 代码如下"></a>1.3 代码如下</h5><pre class=" language-java"><code class="language-java"> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">quicksort</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a<span class="token punctuation">,</span> <span class="token keyword">int</span> L<span class="token punctuation">,</span> <span class="token keyword">int</span> R<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>L <span class="token operator">>=</span> R<span class="token punctuation">)</span> <span class="token keyword">return</span><span class="token punctuation">;</span> <span class="token function">swap</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> L <span class="token operator">+</span> <span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span> Math<span class="token punctuation">.</span><span class="token function">random</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">*</span><span class="token punctuation">(</span>R <span class="token operator">-</span> L <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">,</span>R<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment" spellcheck="true">//随机从R到L上拿一个元素当做积极要排序数的标准，避免万一是顺序的时候，复杂度变成o（N）</span> <span class="token keyword">int</span> p<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token function">partition</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> L<span class="token punctuation">,</span> R<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token function">quicksort</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> L<span class="token punctuation">,</span> p<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span> <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token function">quicksort</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> p<span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span> <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">,</span> R<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">partition</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a<span class="token punctuation">,</span> <span class="token keyword">int</span> L<span class="token punctuation">,</span> <span class="token keyword">int</span> R<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> less <span class="token operator">=</span> L <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">;</span> <span class="token keyword">int</span> more <span class="token operator">=</span> R<span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>L <span class="token operator"><</span> more<span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>a<span class="token punctuation">[</span>L<span class="token punctuation">]</span> <span class="token operator"><</span> a<span class="token punctuation">[</span>R<span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token function">swap</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> <span class="token operator">++</span>less<span class="token punctuation">,</span> L<span class="token operator">++</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment" spellcheck="true">//把less的下一个元素和当前的元素L交换，然后位置加一</span> <span class="token keyword">else</span> <span class="token keyword">if</span><span class="token punctuation">(</span>a<span class="token punctuation">[</span>L<span class="token punctuation">]</span> <span class="token operator">></span> a<span class="token punctuation">[</span>R<span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token function">swap</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> <span class="token operator">--</span>more<span class="token punctuation">,</span> L<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment" spellcheck="true">//把more的上一个元素和L交换，因为这个元素未知，我们就再让他走一遍</span> <span class="token keyword">else</span> L<span class="token operator">++</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token function">swap</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> more<span class="token punctuation">,</span> R<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment" spellcheck="true">//我们把排序的值分为三部分。第一个部分是<，第二部分是=，第三部分是>，在我们给一个数拍完序之后，那么我们把这个数大于</span> <span class="token comment" spellcheck="true">//部分的第一个元素和R交换，也就是把这个元素给了=部分，相当于一个给=部分增加了一个元素，因为等于部分元素就是根据R的标准来的</span> <span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token punctuation">{</span>less<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">,</span> more<span class="token punctuation">}</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">swap</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a<span class="token punctuation">,</span> <span class="token keyword">int</span> p<span class="token punctuation">,</span> <span class="token keyword">int</span> q<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> a<span class="token punctuation">[</span>p<span class="token punctuation">]</span><span class="token punctuation">;</span> a<span class="token punctuation">[</span>p<span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>q<span class="token punctuation">]</span><span class="token punctuation">;</span> a<span class="token punctuation">[</span>q<span class="token punctuation">]</span> <span class="token operator">=</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span></code></pre><h4 id="2-堆排序"><a href="#2-堆排序" class="headerlink" title="2. 堆排序"></a>2. 堆排序</h4><h5 id="2-1-堆排序的原理"><a href="#2-1-堆排序的原理" class="headerlink" title="2.1 堆排序的原理"></a>2.1 堆排序的原理</h5><p> 堆排序就是先根据数据状况建立完全二叉树，当然这个是虚拟的，就像链表的结构一样，在物理内存中是不连续的，以指针的方式连接，在逻辑上是连续的，我们可以画出来。实际上二叉树是虚拟的，而是用数组来表示的。</p><h5 id="2-2-堆排序的实现步骤"><a href="#2-2-堆排序的实现步骤" class="headerlink" title="2.2 堆排序的实现步骤"></a>2.2 堆排序的实现步骤</h5><p> 堆排序的一般步骤，建立最大堆（指的是父节点大于任何一个孩子节点），把最后一个元素放到堆顶，然后元素个数-1，然后重新建立最大堆，以此类推即可</p><h5 id="2-3-具体实现"><a href="#2-3-具体实现" class="headerlink" title="2.3 具体实现"></a>2.3 具体实现</h5><pre class=" language-java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">class</span> 堆排序 <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> a<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token number">6</span><span class="token punctuation">,</span><span class="token number">8</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token number">6</span><span class="token punctuation">,</span><span class="token number">87</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">20</span><span class="token punctuation">}</span><span class="token punctuation">;</span> <span class="token function">heapSort</span><span class="token punctuation">(</span>a<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>a<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">+</span> <span class="token string">" "</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token comment" spellcheck="true">//堆排序的一般步骤，建立最大堆，把最后一个元素放到堆顶，然后元素个数-1，然后重新建立最大堆，以此类推即可</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">heapSort</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>a<span class="token punctuation">.</span>length <span class="token operator"><</span> <span class="token number">2</span> <span class="token operator">||</span> a <span class="token operator">==</span> null<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token function">insertHeap</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> i<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">int</span> heapsize <span class="token operator">=</span> a<span class="token punctuation">.</span>length<span class="token punctuation">;</span> <span class="token function">swap</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">,</span> <span class="token operator">--</span>heapsize<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>heapsize <span class="token operator">></span> <span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token function">heapfiy</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">,</span> heapsize<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token function">swap</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">,</span> <span class="token operator">--</span>heapsize<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">heapfiy</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a<span class="token punctuation">,</span> <span class="token keyword">int</span> i<span class="token punctuation">,</span> <span class="token keyword">int</span> heapsize<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> left <span class="token operator">=</span> i <span class="token operator">*</span> <span class="token number">2</span> <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>left <span class="token operator"><</span> heapsize<span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">int</span> largest <span class="token operator">=</span> left <span class="token operator">+</span> <span class="token number">1</span> <span class="token operator"><</span> heapsize <span class="token operator">&&</span> a<span class="token punctuation">[</span>left <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">]</span> <span class="token operator">></span> a<span class="token punctuation">[</span>left<span class="token punctuation">]</span> <span class="token operator">?</span> left <span class="token operator">+</span> <span class="token number">1</span> <span class="token operator">:</span> left<span class="token punctuation">;</span> <span class="token keyword">if</span><span class="token punctuation">(</span>a<span class="token punctuation">[</span>largest<span class="token punctuation">]</span> <span class="token operator"><=</span> i<span class="token punctuation">)</span> <span class="token keyword">break</span><span class="token punctuation">;</span> <span class="token function">swap</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> largest<span class="token punctuation">,</span> i<span class="token punctuation">)</span><span class="token punctuation">;</span> i <span class="token operator">=</span> largest<span class="token punctuation">;</span> left <span class="token operator">=</span> i <span class="token operator">*</span> <span class="token number">2</span> <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">insertHeap</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a<span class="token punctuation">,</span> <span class="token keyword">int</span> i<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>a<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">></span> a<span class="token punctuation">[</span><span class="token punctuation">(</span>i<span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token operator">/</span><span class="token number">2</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token function">swap</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> i<span class="token punctuation">,</span> <span class="token punctuation">(</span>i<span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token operator">/</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span> i <span class="token operator">=</span> <span class="token punctuation">(</span>i<span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token operator">/</span><span class="token number">2</span><span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token comment" spellcheck="true">//（i-1）/2是a元素的父节点</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">swap</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a<span class="token punctuation">,</span> <span class="token keyword">int</span> p<span class="token punctuation">,</span> <span class="token keyword">int</span> q<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> a<span class="token punctuation">[</span>p<span class="token punctuation">]</span><span class="token punctuation">;</span> a<span class="token punctuation">[</span>p<span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>q<span class="token punctuation">]</span><span class="token punctuation">;</span> a<span class="token punctuation">[</span>q<span class="token punctuation">]</span> <span class="token operator">=</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span></code></pre><h4 id="3-流求任意个数的中位数"><a href="#3-流求任意个数的中位数" class="headerlink" title="3. 流求任意个数的中位数"></a>3. 流求任意个数的中位数</h4><p> 题目是这样描述的，在一个流中随机吐出数字，我要求任意一次的中位数，该怎么办。一般的思路就是，把每一次吐出的数字放在一个容器中，然后排好序，奇数个数字的话就是÷2+1，偶数的话就是中间两个数之和除2，这种办法也是容易想到的办法。但是效果不太理想。第一，我们要消耗容器不说，第二我们要排序，这个代价至少是O（N*logN）。所以说，有一个更好的办法，是用大小堆来做。首先：我们建立的一大堆和一小堆，我们的目的是把N/2个较大数放在右面，N/2个较小的数放在面。此时中位数就很好求了。具体做法如下：第一个进来之后先放入最大堆，然后再来的数，小于他的放在最大堆，大于他的放在最小堆，用二叉树的方式坠链（也就是虚拟的，实际还是数组），每一次检测大小堆个数的差值，如果大于等于2的话，我们就把最大堆的最大元素放入最小堆，让次大元素成为最大堆的最大元素。例如 5 4 6 7，第一次进入5 ，放入最大堆，中位数就是5（当然一个数中位数就是自己，没什么好说的）。第二次进入4，放入最大堆，这时候发现，大小堆个数差值是2，则把最大堆的最大元素放在最小堆中，让次大元素4成为最大堆的最大元素，这时候差值是0，中位数就是（4+5）/2，接下来，是6，大于4，则放入最小堆，7也是如此。但是这时，差值是2了。最大堆元素 4。最小堆元素 5 6 7，这时候同样的，把最小堆的最小元素5放在最大堆中成为最大元素，这时候最大堆 4 5 ，最小堆 6 7，中位数就是堆首元素 （5+6）/2即可。这样用到了堆的知识。听说这几年京东，阿里面试中就有很多堆的问题。</p><p>Lucien</p><p>于2019年5月2日20:01:08 眼睛好难受</p>]]></content>
<categories>
<category> 独孤九剑 </category>
</categories>
<tags>
<tag> 快速排序 </tag>
<tag> 堆排序 </tag>
<tag> 流求任意个数的中位数 </tag>
</tags>
</entry>
<entry>
<title>独孤九剑「马步篇」</title>
<link href="/2018/09/07/du-gu-jiu-jian-ma-bu-pian/"/>
<url>/2018/09/07/du-gu-jiu-jian-ma-bu-pian/</url>
<content type="html"><![CDATA[<h4 id="1-算法复杂度"><a href="#1-算法复杂度" class="headerlink" title="1.算法复杂度"></a>1.算法复杂度</h4><p> 时间复杂度用大o表示，没什么好说的。主要来说下递归的算法复杂度</p><pre><code> T(N) = a*T(N/b) + O(N^d) 1) log(b,a) > d -> 复杂度为O(N^log(b,a)) 2) log(b,a) = d -> 复杂度为O(N^d * logN) 3) log(b,a) < d -> 复杂度为O(N^d) </code></pre><p> 补充阅读： <a href="http://www.gocalf.com/blog/algorithm-complexity-and-mastertheorem.html" target="_blank" rel="noopener">www.gocalf.com/blog/algorithm-complexity-and-mastertheorem.html</a> （虽然我就没看过，哈哈哈哈）</p><p> 举个例子来说一下</p><pre><code> T(N) = 2*T(N/2) + O(N^1) log2 2 = 1 ->复杂度是o（N*logN）</code></pre><h4 id="2-归并排序"><a href="#2-归并排序" class="headerlink" title="2.归并排序"></a>2.归并排序</h4><p> 归并排序的思想是分而治之，把一个大问题转换为同类型的小问题，同类型指的是运算过程，运算逻辑相等，比如说，我想给N个数排序，那么我把这个过程分为三部分，第一部分，我先给0~mid部分排序，然后给mid+1~N排序，然后把两个排好序的序列，再合起来排序，这样就达到了给一个序列排序的过程，类似的，2分之后还有4分，知道一个数就返回。这就是归并排序的思路。</p><p><img src="https://s2.ax1x.com/2019/05/01/EJnWEF.gif" alt="动态案例如下.gif"></p><pre class=" language-java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">class</span> 归并排序 <span class="token punctuation">{</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> a<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">56</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">}</span><span class="token punctuation">;</span> 归并排序算法<span class="token punctuation">(</span>a<span class="token punctuation">,</span><span class="token number">0</span><span class="token punctuation">,</span>a<span class="token punctuation">.</span>length<span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>a<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">+</span> <span class="token string">" "</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> 归并排序算法<span class="token punctuation">(</span><span class="token keyword">int</span> a<span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">,</span> <span class="token keyword">int</span> L<span class="token punctuation">,</span> <span class="token keyword">int</span> R<span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>L <span class="token operator">==</span> R<span class="token punctuation">)</span> <span class="token keyword">return</span><span class="token punctuation">;</span> <span class="token keyword">int</span> mid <span class="token operator">=</span> L <span class="token operator">+</span> <span class="token punctuation">(</span><span class="token punctuation">(</span>R <span class="token operator">-</span> L<span class="token punctuation">)</span> <span class="token operator">>></span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment" spellcheck="true">//防止溢出</span> 归并排序算法<span class="token punctuation">(</span>a<span class="token punctuation">,</span>L<span class="token punctuation">,</span>mid<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment" spellcheck="true">//错误点1：这边不是0,记住是L到mid，因为这个每一次都不一定是L开始的</span> 归并排序算法<span class="token punctuation">(</span>a<span class="token punctuation">,</span>mid<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">,</span>R<span class="token punctuation">)</span><span class="token punctuation">;</span> 整合<span class="token punctuation">(</span>a<span class="token punctuation">,</span> L<span class="token punctuation">,</span> R<span class="token punctuation">,</span> mid<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">void</span> 整合<span class="token punctuation">(</span><span class="token keyword">int</span> a<span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">,</span> <span class="token keyword">int</span> L<span class="token punctuation">,</span> <span class="token keyword">int</span> R<span class="token punctuation">,</span> <span class="token keyword">int</span> mid<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> help<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span>R <span class="token operator">-</span> L <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token comment" spellcheck="true">//错误点2，这边不是a.length,这边应该是L-R+1个个数长度，为什么呢？实际debug表明：如果是a长度的话，</span> <span class="token comment" spellcheck="true">// java会自动生成a长度大小，元素全为0的数组，在最后的覆盖中会把后面那些还没有排好序的元素也替换成0，污染了源数据</span> <span class="token keyword">int</span> count <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token keyword">int</span> p1 <span class="token operator">=</span> L<span class="token punctuation">;</span><span class="token comment" spellcheck="true">//不是0是L</span> <span class="token keyword">int</span> p2 <span class="token operator">=</span> mid <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>p1 <span class="token operator"><=</span> mid <span class="token operator">&&</span> p2 <span class="token operator"><=</span> R<span class="token punctuation">)</span><span class="token punctuation">{</span> help<span class="token punctuation">[</span>count<span class="token operator">++</span><span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>p1<span class="token punctuation">]</span> <span class="token operator"><=</span> a<span class="token punctuation">[</span>p2<span class="token punctuation">]</span><span class="token operator">?</span> a<span class="token punctuation">[</span>p1<span class="token operator">++</span><span class="token punctuation">]</span> <span class="token operator">:</span> a<span class="token punctuation">[</span>p2<span class="token operator">++</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>p1 <span class="token operator"><=</span> mid<span class="token punctuation">)</span><span class="token punctuation">{</span> help<span class="token punctuation">[</span>count<span class="token operator">++</span><span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>p1<span class="token operator">++</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>p2 <span class="token operator"><=</span> R<span class="token punctuation">)</span><span class="token punctuation">{</span> help<span class="token punctuation">[</span>count<span class="token operator">++</span><span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>p2<span class="token operator">++</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> help<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> a<span class="token punctuation">[</span>L <span class="token operator">+</span> i<span class="token punctuation">]</span> <span class="token operator">=</span> help<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token comment" spellcheck="true">//错误点三：这边不是a[i] = help[i];，因为这样做得话，每一次就总会从替换第0个数据，一直覆盖源数据，导致错误</span> <span class="token comment" spellcheck="true">//正确的办法应该是从L开始，因为L是每一次源数据的开始，L+i就是每一次源数据所在位置的加减。</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span><span class="token punctuation">}</span></code></pre><h4 id="3-冒泡排序（自己实现的）"><a href="#3-冒泡排序（自己实现的）" class="headerlink" title="3.冒泡排序（自己实现的）"></a>3.冒泡排序（自己实现的）</h4><pre class=" language-java"><code class="language-java"> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> 冒泡排序<span class="token punctuation">(</span><span class="token keyword">int</span> a<span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token comment" spellcheck="true">//如果左边开始数 第一个大于第二个 就开始交换， 知道最后一个 我们就能得到升序排列，否则就是降序排列</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length<span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> j <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> j <span class="token operator"><</span> a<span class="token punctuation">.</span>length<span class="token operator">-</span><span class="token number">1</span><span class="token operator">-</span>i<span class="token punctuation">;</span> j<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>a<span class="token punctuation">[</span>j<span class="token punctuation">]</span><span class="token operator">></span>a<span class="token punctuation">[</span>j<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> a<span class="token punctuation">[</span>j<span class="token punctuation">]</span><span class="token punctuation">;</span> a<span class="token punctuation">[</span>j<span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>j<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> a<span class="token punctuation">[</span>j<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">]</span> <span class="token operator">=</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span></code></pre><h4 id="4-选择排序（自己实现的）"><a href="#4-选择排序（自己实现的）" class="headerlink" title="4.选择排序（自己实现的）"></a>4.选择排序（自己实现的）</h4><pre class=" language-java"><code class="language-java"> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> 选择排序<span class="token punctuation">(</span><span class="token keyword">int</span> a<span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> Min <span class="token operator">=</span> a<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> j <span class="token operator">=</span> i<span class="token punctuation">;</span> j <span class="token operator"><</span> a<span class="token punctuation">.</span>length<span class="token punctuation">;</span> j<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>Min <span class="token operator">></span> a<span class="token punctuation">[</span>j<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> Min<span class="token punctuation">;</span> Min <span class="token operator">=</span> a<span class="token punctuation">[</span>j<span class="token punctuation">]</span><span class="token punctuation">;</span> a<span class="token punctuation">[</span>j<span class="token punctuation">]</span> <span class="token operator">=</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> a<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">=</span> Min<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span></code></pre><h4 id="5-插入排序（自己实现的）"><a href="#5-插入排序（自己实现的）" class="headerlink" title="5.插入排序（自己实现的）"></a>5.插入排序（自己实现的）</h4><pre class=" language-java"><code class="language-java"> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> 插入排序<span class="token punctuation">(</span><span class="token keyword">int</span> a<span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token comment" spellcheck="true">//一个数据分为两个部分，排好序的有序序列，和无序序列，每次向有序序列中添加一个数字即可。</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> a<span class="token punctuation">.</span>length <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> j <span class="token operator">=</span> i<span class="token punctuation">;</span> j <span class="token operator">>=</span> <span class="token number">0</span><span class="token punctuation">;</span> j<span class="token operator">--</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">if</span><span class="token punctuation">(</span>a<span class="token punctuation">[</span>j<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">]</span> <span class="token operator"><</span> a<span class="token punctuation">[</span>j<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">{</span> <span class="token keyword">int</span> temp <span class="token operator">=</span> a<span class="token punctuation">[</span>j<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> a<span class="token punctuation">[</span>j<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>j<span class="token punctuation">]</span><span class="token punctuation">;</span> a<span class="token punctuation">[</span>j<span class="token punctuation">]</span> <span class="token operator">=</span> temp<span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span></code></pre><h4 id="6-小合问题"><a href="#6-小合问题" class="headerlink" title="6.小合问题"></a>6.小合问题</h4><pre class=" language-java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">class</span> 小合问题 <span class="token punctuation">{</span> <span class="token comment" spellcheck="true">/** * 在一个数组中， 每一个数左边比当前数小的数累加起来， 叫做这个数组的小和。 求一个数组的小和。 * 例子： * [1,3,4,2,5] * 1左边比1小的数， 没有； * 3左边比3小的数， 1； * 4左边比4小的数， 1、 3； * 2左边比2小的数， 1； * 5左边比5小的数， 1、 3、 4、 2； * 所以小和为1+1+3+1+1+3+4+2=16 */</span> <span class="token comment" spellcheck="true">/** * 思路：可以转化为寻找比左边数字大的元素个数*该左边元素即可 */</span> <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token function">litterSum</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">litterSum</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> a<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">5</span><span class="token punctuation">}</span><span class="token punctuation">;</span> System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token function">solveLitterSum</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">,</span> a<span class="token punctuation">.</span>length <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment" spellcheck="true">// for (int i = 0; i < a.length; i++) {</span><span class="token comment" spellcheck="true">// System.out.println(a[i] + " ");</span><span class="token comment" spellcheck="true">// }</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">int</span> <span class="token function">solveLitterSum</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a<span class="token punctuation">,</span> <span class="token keyword">int</span> L<span class="token punctuation">,</span> <span class="token keyword">int</span> R<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token comment" spellcheck="true">//返回值类型发生变化，以前是什么都不返回，现在返回一个整形</span> <span class="token keyword">if</span><span class="token punctuation">(</span>L <span class="token operator">==</span> R<span class="token punctuation">)</span> <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token comment" spellcheck="true">//当两个值一样的时候，就表示碰到了同一个数，所以我们要返回0嘛</span> <span class="token keyword">int</span> mid <span class="token operator">=</span> L <span class="token operator">+</span> <span class="token punctuation">(</span><span class="token punctuation">(</span>R <span class="token operator">-</span> L<span class="token punctuation">)</span> <span class="token operator">>></span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment" spellcheck="true">// solveLitterSum(a,L,mid);</span><span class="token comment" spellcheck="true">// solveLitterSum(a,mid+1,R);</span><span class="token comment" spellcheck="true">// merage(a,L,mid,R);</span> <span class="token keyword">return</span> <span class="token function">solveLitterSum</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span>L<span class="token punctuation">,</span>mid<span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token function">solveLitterSum</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span>mid<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">,</span>R<span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token function">merage</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span>L<span class="token punctuation">,</span>mid<span class="token punctuation">,</span>R<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">int</span> <span class="token function">merage</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> a<span class="token punctuation">,</span> <span class="token keyword">int</span> L<span class="token punctuation">,</span> <span class="token keyword">int</span> mid<span class="token punctuation">,</span> <span class="token keyword">int</span> R<span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">int</span> help<span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">int</span><span class="token punctuation">[</span>R <span class="token operator">-</span> L <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">int</span> count <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token keyword">int</span> p1 <span class="token operator">=</span> L<span class="token punctuation">;</span> <span class="token keyword">int</span> p2 <span class="token operator">=</span> mid <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">;</span> <span class="token keyword">int</span> res <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>p1 <span class="token operator"><=</span> mid <span class="token operator">&&</span> p2 <span class="token operator"><=</span> R<span class="token punctuation">)</span><span class="token punctuation">{</span> res <span class="token operator">+=</span> a<span class="token punctuation">[</span>p1<span class="token punctuation">]</span> <span class="token operator"><</span> a<span class="token punctuation">[</span>p2<span class="token punctuation">]</span> <span class="token operator">?</span> <span class="token punctuation">(</span>R <span class="token operator">-</span> p2 <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token operator">*</span>a<span class="token punctuation">[</span>p1<span class="token punctuation">]</span><span class="token operator">:</span><span class="token number">0</span><span class="token punctuation">;</span> help<span class="token punctuation">[</span>count<span class="token operator">++</span><span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>p1<span class="token punctuation">]</span> <span class="token operator"><=</span> a<span class="token punctuation">[</span>p2<span class="token punctuation">]</span><span class="token operator">?</span> a<span class="token punctuation">[</span>p1<span class="token operator">++</span><span class="token punctuation">]</span> <span class="token operator">:</span> a<span class="token punctuation">[</span>p2<span class="token operator">++</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>p1 <span class="token operator"><=</span> mid<span class="token punctuation">)</span><span class="token punctuation">{</span> help<span class="token punctuation">[</span>count<span class="token operator">++</span><span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>p1<span class="token operator">++</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">while</span> <span class="token punctuation">(</span>p2 <span class="token operator"><=</span> R<span class="token punctuation">)</span><span class="token punctuation">{</span> help<span class="token punctuation">[</span>count<span class="token operator">++</span><span class="token punctuation">]</span> <span class="token operator">=</span> a<span class="token punctuation">[</span>p2<span class="token operator">++</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> help<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> a<span class="token punctuation">[</span>L <span class="token operator">+</span> i<span class="token punctuation">]</span> <span class="token operator">=</span> help<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> res<span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token punctuation">}</span></code></pre>]]></content>
<categories>
<category> 独孤九剑 </category>
</categories>
<tags>
<tag> 算法 </tag>
<tag> 归并排序 </tag>
<tag> 归并排序应用 </tag>
<tag> 冒泡排序 </tag>
<tag> 选择排序 </tag>
<tag> 插入排序 </tag>
<tag> 时间复杂度 </tag>
<tag> 对数器 </tag>
</tags>
</entry>
</search>