This commit is contained in:
krahets 2023-03-21 22:16:25 +08:00
parent ba64311aa8
commit 6116de7118
6 changed files with 161 additions and 73 deletions

View File

@ -1724,28 +1724,24 @@
<h1 id="25">2.5. &nbsp; 小结<a class="headerlink" href="#25" title="Permanent link">&para;</a></h1>
<h3 id="_1">算法效率评估<a class="headerlink" href="#_1" title="Permanent link">&para;</a></h3>
<ul>
<li>时间效率空间效率是算法性能的两个重要的评价维度。</li>
<li>我们可以通过实际测试来评估算法效率,但难以排除测试环境的干扰,并且非常耗费计算资源。</li>
<li>复杂度分析克服了实际测试的弊端,分析结果适用于所有运行平台,并且可以体现不同数据大小下的算法效率。</li>
<li>时间效率和空间效率是算法性能的两个重要的评价维度。</li>
<li>我们可以通过实际测试来评估算法效率,但难以排除测试环境的干扰,并且非常耗费计算资源。</li>
<li>复杂度分析克服了实际测试的弊端,分析结果适用于所有运行平台,并且可以体现不同数据大小下的算法效率。</li>
</ul>
<h3 id="_2">时间复杂度<a class="headerlink" href="#_2" title="Permanent link">&para;</a></h3>
<ul>
<li>时间复杂度统计算法运行时间随着数据量变大时的增长趋势,可以有效评估算法效率,但在某些情况下可能失效,比如在输入数据量较小或时间复杂度相同时,无法精确对比算法效率的优劣性。</li>
<li>最差时间复杂度使用大 <span class="arithmatex">\(O\)</span> 符号表示,即函数渐近上界,其反映当 <span class="arithmatex">\(n\)</span> 趋于正无穷时,<span class="arithmatex">\(T(n)\)</span> 处于何种增长级别。</li>
<li>时间复杂度统计算法运行时间随着数据量变大时的增长趋势,可以有效评估算法效率,但在某些情况下可能失效,比如在输入数据量较小或时间复杂度相同时,无法精确对比算法效率的优劣性。</li>
<li>最差时间复杂度使用大 <span class="arithmatex">\(O\)</span> 符号表示,即函数渐近上界,其反映当 <span class="arithmatex">\(n\)</span> 趋于正无穷时,<span class="arithmatex">\(T(n)\)</span> 处于何种增长级别。</li>
<li>推算时间复杂度分为两步,首先统计计算操作数量,再判断渐近上界。</li>
<li>常见时间复杂度从小到大排列有 <span class="arithmatex">\(O(1)\)</span> , <span class="arithmatex">\(O(\log n)\)</span> , <span class="arithmatex">\(O(n)\)</span> , <span class="arithmatex">\(O(n \log n)\)</span> , <span class="arithmatex">\(O(n^2)\)</span> , <span class="arithmatex">\(O(2^n)\)</span> , <span class="arithmatex">\(O(n!)\)</span></li>
<li>某些算法的时间复杂度不是恒定的,而是与输入数据的分布有关。时间复杂度分为最差时间复杂度最佳时间复杂度,后者几乎不用,因为输入数据需要满足苛刻的条件才能达到最佳情况。</li>
<li>平均时间复杂度可以反映在随机数据输入下的算法效率,最贴合实际使用情况下的算法性能。计算平均时间复杂度需要统计输入数据的分布,以及综合后的数学期望。</li>
<li>某些算法的时间复杂度不是恒定的,而是与输入数据的分布有关。时间复杂度分为最差时间复杂度和最佳时间复杂度,后者几乎不用,因为输入数据需要满足苛刻的条件才能达到最佳情况。</li>
<li>平均时间复杂度可以反映在随机数据输入下的算法效率,最贴合实际使用情况下的算法性能。计算平均时间复杂度需要统计输入数据的分布,以及综合后的数学期望。</li>
</ul>
<h3 id="_3">空间复杂度<a class="headerlink" href="#_3" title="Permanent link">&para;</a></h3>
<ul>
<li>
<p>与时间复杂度的定义类似,「空间复杂度」统计算法占用空间随着数据量变大时的增长趋势。</p>
</li>
<li>
<p>算法运行中相关内存空间可分为输入空间、暂存空间、输出空间。通常情况下,输入空间不计入空间复杂度计算。暂存空间可分为指令空间、数据空间、栈帧空间,其中栈帧空间一般在递归函数中才会影响到空间复杂度。</p>
</li>
<li>我们一般只关心「最差空间复杂度」,即统计算法在「最差输入数据」和「最差运行时间点」下的空间复杂度。</li>
<li>与时间复杂度的定义类似,空间复杂度统计算法占用空间随着数据量变大时的增长趋势。</li>
<li>算法运行中相关内存空间可分为输入空间、暂存空间、输出空间。通常情况下,输入空间不计入空间复杂度计算。暂存空间可分为指令空间、数据空间、栈帧空间,其中栈帧空间一般在递归函数中才会影响到空间复杂度。</li>
<li>我们一般只关心最差空间复杂度,即统计算法在最差输入数据和最差运行时间点下的空间复杂度。</li>
<li>常见空间复杂度从小到大排列有 <span class="arithmatex">\(O(1)\)</span> , <span class="arithmatex">\(O(\log n)\)</span> , <span class="arithmatex">\(O(n)\)</span> , <span class="arithmatex">\(O(n^2)\)</span> , <span class="arithmatex">\(O(2^n)\)</span></li>
</ul>

View File

@ -1812,7 +1812,7 @@ G &amp; = \{ V, E \} \newline
<h2 id="912">9.1.2. &nbsp; 图常用术语<a class="headerlink" href="#912" title="Permanent link">&para;</a></h2>
<ul>
<li>「邻接 Adjacency」当两顶点之间有边相连时称此两顶点“邻接”。例如上图中顶点 1 的邻接顶点为顶点 2, 3, 5 。</li>
<li>「路径 Path」从顶点 A 到顶点 B 走过的边构成的序列,被称为从 A 到 B 的“路径”。例如,上图中 1, 5, 2, 4 是顶点 1 到顶点 4 的一个路径。</li>
<li>「路径 Path」从顶点 A 到顶点 B 走过的边构成的序列,被称为从 A 到 B 的“路径”。例如,上图中边序列 1-5-2-4 是顶点 1 到顶点 4 的一个路径。</li>
<li>「度 Degree」表示一个顶点具有多少条边。对于有向图「入度 In-Degree」表示有多少条边指向该顶点「出度 Out-Degree」表示有多少条边从该顶点指出。</li>
</ul>
<h2 id="913">9.1.3. &nbsp; 图的表示<a class="headerlink" href="#913" title="Permanent link">&para;</a></h2>

View File

@ -1786,11 +1786,49 @@
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">counting_sort.cpp</span><pre><span></span><code><a id="__codelineno-1-1" name="__codelineno-1-1" href="#__codelineno-1-1"></a><span class="p">[</span><span class="k">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">countingSortNaive</span><span class="p">}</span>
<div class="highlight"><span class="filename">counting_sort.cpp</span><pre><span></span><code><a id="__codelineno-1-1" name="__codelineno-1-1" href="#__codelineno-1-1"></a><span class="cm">/* 计数排序 */</span>
<a id="__codelineno-1-2" name="__codelineno-1-2" href="#__codelineno-1-2"></a><span class="c1">// 简单实现,无法用于排序对象</span>
<a id="__codelineno-1-3" name="__codelineno-1-3" href="#__codelineno-1-3"></a><span class="kt">void</span><span class="w"> </span><span class="nf">countingSortNaive</span><span class="p">(</span><span class="n">vector</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;&amp;</span><span class="w"> </span><span class="n">nums</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-1-4" name="__codelineno-1-4" href="#__codelineno-1-4"></a><span class="w"> </span><span class="c1">// 1. 统计数组最大元素 m</span>
<a id="__codelineno-1-5" name="__codelineno-1-5" href="#__codelineno-1-5"></a><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">m</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span>
<a id="__codelineno-1-6" name="__codelineno-1-6" href="#__codelineno-1-6"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">num</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="n">nums</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-1-7" name="__codelineno-1-7" href="#__codelineno-1-7"></a><span class="w"> </span><span class="n">m</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">max</span><span class="p">(</span><span class="n">m</span><span class="p">,</span><span class="w"> </span><span class="n">num</span><span class="p">);</span>
<a id="__codelineno-1-8" name="__codelineno-1-8" href="#__codelineno-1-8"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-1-9" name="__codelineno-1-9" href="#__codelineno-1-9"></a><span class="w"> </span><span class="c1">// 2. 统计各数字的出现次数</span>
<a id="__codelineno-1-10" name="__codelineno-1-10" href="#__codelineno-1-10"></a><span class="w"> </span><span class="c1">// counter[num] 代表 num 的出现次数</span>
<a id="__codelineno-1-11" name="__codelineno-1-11" href="#__codelineno-1-11"></a><span class="w"> </span><span class="n">vector</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;</span><span class="w"> </span><span class="n">counter</span><span class="p">(</span><span class="n">m</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">0</span><span class="p">);</span>
<a id="__codelineno-1-12" name="__codelineno-1-12" href="#__codelineno-1-12"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">num</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="n">nums</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-1-13" name="__codelineno-1-13" href="#__codelineno-1-13"></a><span class="w"> </span><span class="n">counter</span><span class="p">[</span><span class="n">num</span><span class="p">]</span><span class="o">++</span><span class="p">;</span>
<a id="__codelineno-1-14" name="__codelineno-1-14" href="#__codelineno-1-14"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-1-15" name="__codelineno-1-15" href="#__codelineno-1-15"></a><span class="w"> </span><span class="c1">// 3. 遍历 counter ,将各元素填入原数组 nums</span>
<a id="__codelineno-1-16" name="__codelineno-1-16" href="#__codelineno-1-16"></a><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span>
<a id="__codelineno-1-17" name="__codelineno-1-17" href="#__codelineno-1-17"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">num</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">num</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">m</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span><span class="w"> </span><span class="n">num</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-1-18" name="__codelineno-1-18" href="#__codelineno-1-18"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">j</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">j</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">counter</span><span class="p">[</span><span class="n">num</span><span class="p">];</span><span class="w"> </span><span class="n">j</span><span class="o">++</span><span class="p">,</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-1-19" name="__codelineno-1-19" href="#__codelineno-1-19"></a><span class="w"> </span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">num</span><span class="p">;</span>
<a id="__codelineno-1-20" name="__codelineno-1-20" href="#__codelineno-1-20"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-1-21" name="__codelineno-1-21" href="#__codelineno-1-21"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-1-22" name="__codelineno-1-22" href="#__codelineno-1-22"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">counting_sort.py</span><pre><span></span><code><a id="__codelineno-2-1" name="__codelineno-2-1" href="#__codelineno-2-1"></a><span class="p">[</span><span class="n">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">counting_sort_naive</span><span class="p">}</span>
<div class="highlight"><span class="filename">counting_sort.py</span><pre><span></span><code><a id="__codelineno-2-1" name="__codelineno-2-1" href="#__codelineno-2-1"></a><span class="k">def</span> <span class="nf">counting_sort_naive</span><span class="p">(</span><span class="n">nums</span><span class="p">:</span> <span class="n">List</span><span class="p">[</span><span class="nb">int</span><span class="p">])</span> <span class="o">-&gt;</span> <span class="kc">None</span><span class="p">:</span>
<a id="__codelineno-2-2" name="__codelineno-2-2" href="#__codelineno-2-2"></a><span class="w"> </span><span class="sd">&quot;&quot;&quot; 计数排序 &quot;&quot;&quot;</span>
<a id="__codelineno-2-3" name="__codelineno-2-3" href="#__codelineno-2-3"></a> <span class="c1"># 简单实现,无法用于排序对象</span>
<a id="__codelineno-2-4" name="__codelineno-2-4" href="#__codelineno-2-4"></a> <span class="c1"># 1. 统计数组最大元素 m</span>
<a id="__codelineno-2-5" name="__codelineno-2-5" href="#__codelineno-2-5"></a> <span class="n">m</span> <span class="o">=</span> <span class="mi">0</span>
<a id="__codelineno-2-6" name="__codelineno-2-6" href="#__codelineno-2-6"></a> <span class="k">for</span> <span class="n">num</span> <span class="ow">in</span> <span class="n">nums</span><span class="p">:</span>
<a id="__codelineno-2-7" name="__codelineno-2-7" href="#__codelineno-2-7"></a> <span class="n">m</span> <span class="o">=</span> <span class="nb">max</span><span class="p">(</span><span class="n">m</span><span class="p">,</span> <span class="n">num</span><span class="p">)</span>
<a id="__codelineno-2-8" name="__codelineno-2-8" href="#__codelineno-2-8"></a> <span class="c1"># 2. 统计各数字的出现次数</span>
<a id="__codelineno-2-9" name="__codelineno-2-9" href="#__codelineno-2-9"></a> <span class="c1"># counter[num] 代表 num 的出现次数</span>
<a id="__codelineno-2-10" name="__codelineno-2-10" href="#__codelineno-2-10"></a> <span class="n">counter</span> <span class="o">=</span> <span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">*</span> <span class="p">(</span><span class="n">m</span> <span class="o">+</span> <span class="mi">1</span><span class="p">)</span>
<a id="__codelineno-2-11" name="__codelineno-2-11" href="#__codelineno-2-11"></a> <span class="k">for</span> <span class="n">num</span> <span class="ow">in</span> <span class="n">nums</span><span class="p">:</span>
<a id="__codelineno-2-12" name="__codelineno-2-12" href="#__codelineno-2-12"></a> <span class="n">counter</span><span class="p">[</span><span class="n">num</span><span class="p">]</span> <span class="o">+=</span> <span class="mi">1</span>
<a id="__codelineno-2-13" name="__codelineno-2-13" href="#__codelineno-2-13"></a> <span class="c1"># 3. 遍历 counter ,将各元素填入原数组 nums</span>
<a id="__codelineno-2-14" name="__codelineno-2-14" href="#__codelineno-2-14"></a> <span class="n">i</span> <span class="o">=</span> <span class="mi">0</span>
<a id="__codelineno-2-15" name="__codelineno-2-15" href="#__codelineno-2-15"></a> <span class="k">for</span> <span class="n">num</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">m</span> <span class="o">+</span> <span class="mi">1</span><span class="p">):</span>
<a id="__codelineno-2-16" name="__codelineno-2-16" href="#__codelineno-2-16"></a> <span class="k">for</span> <span class="n">_</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">counter</span><span class="p">[</span><span class="n">num</span><span class="p">]):</span>
<a id="__codelineno-2-17" name="__codelineno-2-17" href="#__codelineno-2-17"></a> <span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="n">num</span>
<a id="__codelineno-2-18" name="__codelineno-2-18" href="#__codelineno-2-18"></a> <span class="n">i</span> <span class="o">+=</span> <span class="mi">1</span>
</code></pre></div>
</div>
<div class="tabbed-block">
@ -1926,11 +1964,65 @@
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">counting_sort.cpp</span><pre><span></span><code><a id="__codelineno-11-1" name="__codelineno-11-1" href="#__codelineno-11-1"></a><span class="p">[</span><span class="k">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">countingSort</span><span class="p">}</span>
<div class="highlight"><span class="filename">counting_sort.cpp</span><pre><span></span><code><a id="__codelineno-11-1" name="__codelineno-11-1" href="#__codelineno-11-1"></a><span class="cm">/* 计数排序 */</span>
<a id="__codelineno-11-2" name="__codelineno-11-2" href="#__codelineno-11-2"></a><span class="c1">// 完整实现,可排序对象,并且是稳定排序</span>
<a id="__codelineno-11-3" name="__codelineno-11-3" href="#__codelineno-11-3"></a><span class="kt">void</span><span class="w"> </span><span class="nf">countingSort</span><span class="p">(</span><span class="n">vector</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;&amp;</span><span class="w"> </span><span class="n">nums</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-11-4" name="__codelineno-11-4" href="#__codelineno-11-4"></a><span class="w"> </span><span class="c1">// 1. 统计数组最大元素 m</span>
<a id="__codelineno-11-5" name="__codelineno-11-5" href="#__codelineno-11-5"></a><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">m</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span>
<a id="__codelineno-11-6" name="__codelineno-11-6" href="#__codelineno-11-6"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">num</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="n">nums</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-11-7" name="__codelineno-11-7" href="#__codelineno-11-7"></a><span class="w"> </span><span class="n">m</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">max</span><span class="p">(</span><span class="n">m</span><span class="p">,</span><span class="w"> </span><span class="n">num</span><span class="p">);</span>
<a id="__codelineno-11-8" name="__codelineno-11-8" href="#__codelineno-11-8"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-11-9" name="__codelineno-11-9" href="#__codelineno-11-9"></a><span class="w"> </span><span class="c1">// 2. 统计各数字的出现次数</span>
<a id="__codelineno-11-10" name="__codelineno-11-10" href="#__codelineno-11-10"></a><span class="w"> </span><span class="c1">// counter[num] 代表 num 的出现次数</span>
<a id="__codelineno-11-11" name="__codelineno-11-11" href="#__codelineno-11-11"></a><span class="w"> </span><span class="n">vector</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;</span><span class="w"> </span><span class="n">counter</span><span class="p">(</span><span class="n">m</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">0</span><span class="p">);</span>
<a id="__codelineno-11-12" name="__codelineno-11-12" href="#__codelineno-11-12"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">num</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="n">nums</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-11-13" name="__codelineno-11-13" href="#__codelineno-11-13"></a><span class="w"> </span><span class="n">counter</span><span class="p">[</span><span class="n">num</span><span class="p">]</span><span class="o">++</span><span class="p">;</span>
<a id="__codelineno-11-14" name="__codelineno-11-14" href="#__codelineno-11-14"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-11-15" name="__codelineno-11-15" href="#__codelineno-11-15"></a><span class="w"> </span><span class="c1">// 3. 求 counter 的前缀和,将“出现次数”转换为“尾索引”</span>
<a id="__codelineno-11-16" name="__codelineno-11-16" href="#__codelineno-11-16"></a><span class="w"> </span><span class="c1">// 即 counter[num]-1 是 num 在 res 中最后一次出现的索引</span>
<a id="__codelineno-11-17" name="__codelineno-11-17" href="#__codelineno-11-17"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">m</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-11-18" name="__codelineno-11-18" href="#__codelineno-11-18"></a><span class="w"> </span><span class="n">counter</span><span class="p">[</span><span class="n">i</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p">]</span><span class="w"> </span><span class="o">+=</span><span class="w"> </span><span class="n">counter</span><span class="p">[</span><span class="n">i</span><span class="p">];</span>
<a id="__codelineno-11-19" name="__codelineno-11-19" href="#__codelineno-11-19"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-11-20" name="__codelineno-11-20" href="#__codelineno-11-20"></a><span class="w"> </span><span class="c1">// 4. 倒序遍历 nums ,将各元素填入结果数组 res</span>
<a id="__codelineno-11-21" name="__codelineno-11-21" href="#__codelineno-11-21"></a><span class="w"> </span><span class="c1">// 初始化数组 res 用于记录结果</span>
<a id="__codelineno-11-22" name="__codelineno-11-22" href="#__codelineno-11-22"></a><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">n</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">nums</span><span class="p">.</span><span class="n">size</span><span class="p">();</span>
<a id="__codelineno-11-23" name="__codelineno-11-23" href="#__codelineno-11-23"></a><span class="w"> </span><span class="n">vector</span><span class="o">&lt;</span><span class="kt">int</span><span class="o">&gt;</span><span class="w"> </span><span class="n">res</span><span class="p">(</span><span class="n">n</span><span class="p">);</span>
<a id="__codelineno-11-24" name="__codelineno-11-24" href="#__codelineno-11-24"></a><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">n</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&gt;=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">--</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<a id="__codelineno-11-25" name="__codelineno-11-25" href="#__codelineno-11-25"></a><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">num</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">];</span>
<a id="__codelineno-11-26" name="__codelineno-11-26" href="#__codelineno-11-26"></a><span class="w"> </span><span class="n">res</span><span class="p">[</span><span class="n">counter</span><span class="p">[</span><span class="n">num</span><span class="p">]</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="mi">1</span><span class="p">]</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">num</span><span class="p">;</span><span class="w"> </span><span class="c1">// 将 num 放置到对应索引处</span>
<a id="__codelineno-11-27" name="__codelineno-11-27" href="#__codelineno-11-27"></a><span class="w"> </span><span class="n">counter</span><span class="p">[</span><span class="n">num</span><span class="p">]</span><span class="o">--</span><span class="p">;</span><span class="w"> </span><span class="c1">// 令前缀和自减 1 ,得到下次放置 num 的索引</span>
<a id="__codelineno-11-28" name="__codelineno-11-28" href="#__codelineno-11-28"></a><span class="w"> </span><span class="p">}</span>
<a id="__codelineno-11-29" name="__codelineno-11-29" href="#__codelineno-11-29"></a><span class="w"> </span><span class="c1">// 使用结果数组 res 覆盖原数组 nums</span>
<a id="__codelineno-11-30" name="__codelineno-11-30" href="#__codelineno-11-30"></a><span class="w"> </span><span class="n">nums</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">res</span><span class="p">;</span>
<a id="__codelineno-11-31" name="__codelineno-11-31" href="#__codelineno-11-31"></a><span class="p">}</span>
</code></pre></div>
</div>
<div class="tabbed-block">
<div class="highlight"><span class="filename">counting_sort.py</span><pre><span></span><code><a id="__codelineno-12-1" name="__codelineno-12-1" href="#__codelineno-12-1"></a><span class="p">[</span><span class="n">class</span><span class="p">]{}</span><span class="o">-</span><span class="p">[</span><span class="n">func</span><span class="p">]{</span><span class="n">counting_sort</span><span class="p">}</span>
<div class="highlight"><span class="filename">counting_sort.py</span><pre><span></span><code><a id="__codelineno-12-1" name="__codelineno-12-1" href="#__codelineno-12-1"></a><span class="k">def</span> <span class="nf">counting_sort</span><span class="p">(</span><span class="n">nums</span><span class="p">:</span> <span class="n">List</span><span class="p">[</span><span class="nb">int</span><span class="p">])</span> <span class="o">-&gt;</span> <span class="kc">None</span><span class="p">:</span>
<a id="__codelineno-12-2" name="__codelineno-12-2" href="#__codelineno-12-2"></a><span class="w"> </span><span class="sd">&quot;&quot;&quot; 计数排序 &quot;&quot;&quot;</span>
<a id="__codelineno-12-3" name="__codelineno-12-3" href="#__codelineno-12-3"></a> <span class="c1"># 完整实现,可排序对象,并且是稳定排序</span>
<a id="__codelineno-12-4" name="__codelineno-12-4" href="#__codelineno-12-4"></a> <span class="c1"># 1. 统计数组最大元素 m</span>
<a id="__codelineno-12-5" name="__codelineno-12-5" href="#__codelineno-12-5"></a> <span class="n">m</span> <span class="o">=</span> <span class="nb">max</span><span class="p">(</span><span class="n">nums</span><span class="p">)</span>
<a id="__codelineno-12-6" name="__codelineno-12-6" href="#__codelineno-12-6"></a> <span class="c1"># 2. 统计各数字的出现次数</span>
<a id="__codelineno-12-7" name="__codelineno-12-7" href="#__codelineno-12-7"></a> <span class="c1"># counter[num] 代表 num 的出现次数</span>
<a id="__codelineno-12-8" name="__codelineno-12-8" href="#__codelineno-12-8"></a> <span class="n">counter</span> <span class="o">=</span> <span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">*</span> <span class="p">(</span><span class="n">m</span> <span class="o">+</span> <span class="mi">1</span><span class="p">)</span>
<a id="__codelineno-12-9" name="__codelineno-12-9" href="#__codelineno-12-9"></a> <span class="k">for</span> <span class="n">num</span> <span class="ow">in</span> <span class="n">nums</span><span class="p">:</span>
<a id="__codelineno-12-10" name="__codelineno-12-10" href="#__codelineno-12-10"></a> <span class="n">counter</span><span class="p">[</span><span class="n">num</span><span class="p">]</span> <span class="o">+=</span> <span class="mi">1</span>
<a id="__codelineno-12-11" name="__codelineno-12-11" href="#__codelineno-12-11"></a> <span class="c1"># 3. 求 counter 的前缀和,将“出现次数”转换为“尾索引”</span>
<a id="__codelineno-12-12" name="__codelineno-12-12" href="#__codelineno-12-12"></a> <span class="c1"># 即 counter[num]-1 是 num 在 res 中最后一次出现的索引</span>
<a id="__codelineno-12-13" name="__codelineno-12-13" href="#__codelineno-12-13"></a> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">m</span><span class="p">):</span>
<a id="__codelineno-12-14" name="__codelineno-12-14" href="#__codelineno-12-14"></a> <span class="n">counter</span><span class="p">[</span><span class="n">i</span> <span class="o">+</span> <span class="mi">1</span><span class="p">]</span> <span class="o">+=</span> <span class="n">counter</span><span class="p">[</span><span class="n">i</span><span class="p">]</span>
<a id="__codelineno-12-15" name="__codelineno-12-15" href="#__codelineno-12-15"></a> <span class="c1"># 4. 倒序遍历 nums ,将各元素填入结果数组 res</span>
<a id="__codelineno-12-16" name="__codelineno-12-16" href="#__codelineno-12-16"></a> <span class="c1"># 初始化数组 res 用于记录结果</span>
<a id="__codelineno-12-17" name="__codelineno-12-17" href="#__codelineno-12-17"></a> <span class="n">n</span> <span class="o">=</span> <span class="nb">len</span><span class="p">(</span><span class="n">nums</span><span class="p">)</span>
<a id="__codelineno-12-18" name="__codelineno-12-18" href="#__codelineno-12-18"></a> <span class="n">res</span> <span class="o">=</span> <span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">*</span> <span class="n">n</span>
<a id="__codelineno-12-19" name="__codelineno-12-19" href="#__codelineno-12-19"></a> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">n</span> <span class="o">-</span> <span class="mi">1</span><span class="p">,</span> <span class="o">-</span><span class="mi">1</span><span class="p">,</span> <span class="o">-</span><span class="mi">1</span><span class="p">):</span>
<a id="__codelineno-12-20" name="__codelineno-12-20" href="#__codelineno-12-20"></a> <span class="n">num</span> <span class="o">=</span> <span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]</span>
<a id="__codelineno-12-21" name="__codelineno-12-21" href="#__codelineno-12-21"></a> <span class="n">res</span><span class="p">[</span><span class="n">counter</span><span class="p">[</span><span class="n">num</span><span class="p">]</span> <span class="o">-</span> <span class="mi">1</span><span class="p">]</span> <span class="o">=</span> <span class="n">num</span> <span class="c1"># 将 num 放置到对应索引处</span>
<a id="__codelineno-12-22" name="__codelineno-12-22" href="#__codelineno-12-22"></a> <span class="n">counter</span><span class="p">[</span><span class="n">num</span><span class="p">]</span> <span class="o">-=</span> <span class="mi">1</span> <span class="c1"># 令前缀和自减 1 ,得到下次放置 num 的索引</span>
<a id="__codelineno-12-23" name="__codelineno-12-23" href="#__codelineno-12-23"></a> <span class="c1"># 使用结果数组 res 覆盖原数组 nums</span>
<a id="__codelineno-12-24" name="__codelineno-12-24" href="#__codelineno-12-24"></a> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">n</span><span class="p">):</span>
<a id="__codelineno-12-25" name="__codelineno-12-25" href="#__codelineno-12-25"></a> <span class="n">nums</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="n">res</span><span class="p">[</span><span class="n">i</span><span class="p">]</span>
</code></pre></div>
</div>
<div class="tabbed-block">

File diff suppressed because one or more lines are too long

View File

@ -2,267 +2,267 @@
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<url>
<loc>https://www.hello-algo.com/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_appendix/contribution/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_appendix/installation/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_array_and_linkedlist/array/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_array_and_linkedlist/linked_list/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_array_and_linkedlist/list/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_array_and_linkedlist/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_computational_complexity/performance_evaluation/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_computational_complexity/space_complexity/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_computational_complexity/space_time_tradeoff/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_computational_complexity/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_computational_complexity/time_complexity/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_data_structure/classification_of_data_structure/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_data_structure/data_and_memory/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_data_structure/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_graph/graph/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_graph/graph_operations/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_graph/graph_traversal/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_graph/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_hashing/hash_collision/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_hashing/hash_map/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_hashing/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_heap/build_heap/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_heap/heap/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_heap/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_introduction/algorithms_are_everywhere/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_introduction/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_introduction/what_is_dsa/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_preface/about_the_book/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_preface/suggestions/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_preface/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_reference/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_searching/binary_search/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_searching/hashing_search/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_searching/linear_search/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_searching/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_sorting/bubble_sort/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_sorting/bucket_sort/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_sorting/counting_sort/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_sorting/insertion_sort/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_sorting/intro_to_sort/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_sorting/merge_sort/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_sorting/quick_sort/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_sorting/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_stack_and_queue/deque/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_stack_and_queue/queue/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_stack_and_queue/stack/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_stack_and_queue/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_tree/avl_tree/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_tree/binary_search_tree/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_tree/binary_tree/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_tree/binary_tree_traversal/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
<url>
<loc>https://www.hello-algo.com/chapter_tree/summary/</loc>
<lastmod>2023-03-20</lastmod>
<lastmod>2023-03-21</lastmod>
<changefreq>daily</changefreq>
</url>
</urlset>

Binary file not shown.