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<div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno"> 1</span><span class="comment">// C++ program for Huffman Coding</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno"> 2</span><span class="preprocessor">#include &lt;iostream&gt;</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno"> 3</span><span class="preprocessor">#include &lt;queue&gt;</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno"> 4</span><span class="keyword">using namespace </span>std;</div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno"> 5</span> </div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno"> 6</span><span class="comment">// A Huffman tree node</span></div>
<div class="foldopen" id="foldopen00007" data-start="{" data-end="};">
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno"><a class="line" href="../../d5/d29/struct_min_heap_node.html"> 7</a></span><span class="keyword">struct </span>MinHeapNode {</div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno"> 8</span> <span class="comment">// One of the input characters</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno"> 9</span> <span class="keywordtype">char</span> data;</div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno"> 10</span> </div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno"> 11</span> <span class="comment">// Frequency of the character</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno"> 12</span> <span class="keywordtype">unsigned</span> freq;</div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno"> 13</span> </div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno"> 14</span> <span class="comment">// Left and right child</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno"> 15</span> MinHeapNode *left, *right;</div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno"> 16</span> </div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno"> 17</span> MinHeapNode(<span class="keywordtype">char</span> data, <span class="keywordtype">unsigned</span> freq)</div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno"> 18</span> </div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno"> 19</span> {</div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno"> 20</span> left = right = NULL;</div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno"> 21</span> this-&gt;data = data;</div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno"> 22</span> this-&gt;freq = freq;</div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno"> 23</span> }</div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno"> 24</span>};</div>
</div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno"> 25</span> </div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno"> 26</span><span class="keywordtype">void</span> deleteAll(<span class="keyword">const</span> <a class="code hl_struct" href="../../d5/d29/struct_min_heap_node.html">MinHeapNode</a>* <span class="keyword">const</span> root) {</div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno"> 27</span> <span class="keywordflow">if</span> (root) {</div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno"> 28</span> deleteAll(root-&gt;left);</div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno"> 29</span> deleteAll(root-&gt;right);</div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno"> 30</span> <span class="keyword">delete</span> root;</div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno"> 31</span> }</div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno"> 32</span>}</div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno"> 33</span> </div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno"> 34</span><span class="comment">// For comparison of</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno"> 35</span><span class="comment">// two heap nodes (needed in min heap)</span></div>
<div class="foldopen" id="foldopen00036" data-start="{" data-end="};">
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno"><a class="line" href="../../d1/db3/structcompare.html"> 36</a></span><span class="keyword">struct </span><a class="code hl_struct" href="../../d1/db3/structcompare.html">compare</a> {</div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno"> 37</span> <span class="keywordtype">bool</span> operator()(<span class="keyword">const</span> <a class="code hl_struct" href="../../d5/d29/struct_min_heap_node.html">MinHeapNode</a>* <span class="keyword">const</span> l,</div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno"> 38</span> <span class="keyword">const</span> <a class="code hl_struct" href="../../d5/d29/struct_min_heap_node.html">MinHeapNode</a>* <span class="keyword">const</span> r)<span class="keyword"> const </span>{</div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno"> 39</span> <span class="keywordflow">return</span> l-&gt;freq &gt; r-&gt;freq;</div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno"> 40</span> }</div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno"> 41</span>};</div>
</div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno"> 42</span> </div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno"> 43</span><span class="comment">// Prints huffman codes from</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno"> 44</span><span class="comment">// the root of Huffman Tree.</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno"> 45</span><span class="keywordtype">void</span> printCodes(<span class="keyword">struct</span> <a class="code hl_struct" href="../../d5/d29/struct_min_heap_node.html">MinHeapNode</a>* root, <span class="keyword">const</span> <span class="keywordtype">string</span>&amp; str) {</div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno"> 46</span> <span class="keywordflow">if</span> (!root)</div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno"> 47</span> <span class="keywordflow">return</span>;</div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno"> 48</span> </div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno"> 49</span> <span class="keywordflow">if</span> (root-&gt;data != <span class="charliteral">&#39;$&#39;</span>)</div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno"> 50</span> cout &lt;&lt; root-&gt;data &lt;&lt; <span class="stringliteral">&quot;: &quot;</span> &lt;&lt; str &lt;&lt; <span class="stringliteral">&quot;\n&quot;</span>;</div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno"> 51</span> </div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno"> 52</span> printCodes(root-&gt;left, str + <span class="stringliteral">&quot;0&quot;</span>);</div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno"> 53</span> printCodes(root-&gt;right, str + <span class="stringliteral">&quot;1&quot;</span>);</div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno"> 54</span>}</div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno"> 55</span> </div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno"> 56</span><span class="comment">// The main function that builds a Huffman Tree and</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno"> 57</span><span class="comment">// print codes by traversing the built Huffman Tree</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno"> 58</span><span class="keywordtype">void</span> HuffmanCodes(<span class="keyword">const</span> <span class="keywordtype">char</span> <a class="code hl_variable" href="../../d1/df3/hash__search_8cpp.html#a6e1a77282bc65ad359d753d25df23243">data</a>[], <span class="keyword">const</span> <span class="keywordtype">int</span> freq[], <span class="keywordtype">int</span> size) {</div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno"> 59</span> <span class="keyword">struct </span><a class="code hl_struct" href="../../d5/d29/struct_min_heap_node.html">MinHeapNode</a> *left, *right;</div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno"> 60</span> </div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno"> 61</span> <span class="comment">// Create a min heap &amp; inserts all characters of data[]</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno"> 62</span> priority_queue&lt;MinHeapNode*, vector&lt;MinHeapNode*&gt;, <a class="code hl_struct" href="../../d1/db3/structcompare.html">compare</a>&gt; minHeap;</div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno"> 63</span> </div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno"> 64</span> <span class="keywordflow">for</span> (<span class="keywordtype">int</span> i = 0; i &lt; size; ++i)</div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno"> 65</span> minHeap.push(<span class="keyword">new</span> <a class="code hl_struct" href="../../d5/d29/struct_min_heap_node.html">MinHeapNode</a>(<a class="code hl_variable" href="../../d1/df3/hash__search_8cpp.html#a6e1a77282bc65ad359d753d25df23243">data</a>[i], freq[i]));</div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno"> 66</span> </div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno"> 67</span> <span class="comment">// Iterate while size of heap doesn&#39;t become 1</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno"> 68</span> <span class="keywordflow">while</span> (minHeap.size() != 1) {</div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno"> 69</span> <span class="comment">// Extract the two minimum</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno"> 70</span> <span class="comment">// freq items from min heap</span></div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno"> 71</span> left = minHeap.top();</div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno"> 72</span> minHeap.pop();</div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno"> 73</span> </div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno"> 74</span> right = minHeap.top();</div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno"> 75</span> minHeap.pop();</div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno"> 76</span> </div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno"> 77</span> <span class="comment">// Create a new internal node with</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno"> 78</span> <span class="comment">// frequency equal to the sum of the</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno"> 79</span> <span class="comment">// two nodes frequencies. Make the</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno"> 80</span> <span class="comment">// two extracted node as left and right children</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno"> 81</span> <span class="comment">// of this new node. Add this node</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno"> 82</span> <span class="comment">// to the min heap &#39;$&#39; is a special value</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno"> 83</span> <span class="comment">// for internal nodes, not used</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno"> 84</span> <span class="keyword">auto</span>* <span class="keyword">const</span> top = <span class="keyword">new</span> <a class="code hl_struct" href="../../d5/d29/struct_min_heap_node.html">MinHeapNode</a>(<span class="charliteral">&#39;$&#39;</span>, left-&gt;freq + right-&gt;freq);</div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno"> 85</span> </div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno"> 86</span> top-&gt;left = left;</div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno"> 87</span> top-&gt;right = right;</div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno"> 88</span> </div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno"> 89</span> minHeap.push(top);</div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno"> 90</span> }</div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno"> 91</span> </div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno"> 92</span> <span class="comment">// Print Huffman codes using</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno"> 93</span> <span class="comment">// the Huffman tree built above</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno"> 94</span> printCodes(minHeap.top(), <span class="stringliteral">&quot;&quot;</span>);</div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno"> 95</span> deleteAll(minHeap.top());</div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno"> 96</span>}</div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno"> 97</span> </div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno"> 98</span><span class="comment">// Driver program to test above functions</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno"> 99</span><span class="keywordtype">int</span> <a class="code hl_function" href="../../dd/d1e/generate__parentheses_8cpp.html#gae66f6b31b5ad750f1fe042a706a4e3d4">main</a>() {</div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno"> 100</span> <span class="keywordtype">char</span> arr[] = {<span class="charliteral">&#39;a&#39;</span>, <span class="charliteral">&#39;b&#39;</span>, <span class="charliteral">&#39;c&#39;</span>, <span class="charliteral">&#39;d&#39;</span>, <span class="charliteral">&#39;e&#39;</span>, <span class="charliteral">&#39;f&#39;</span>};</div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno"> 101</span> <span class="keywordtype">int</span> freq[] = {5, 9, 12, 13, 16, 45};</div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno"> 102</span> </div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno"> 103</span> <span class="keywordtype">int</span> size = <span class="keyword">sizeof</span>(arr) / <span class="keyword">sizeof</span>(arr[0]);</div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno"> 104</span> </div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno"> 105</span> HuffmanCodes(arr, freq, size);</div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno"> 106</span> </div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno"> 107</span> <span class="keywordflow">return</span> 0;</div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno"> 108</span>}</div>
<div class="ttc" id="agenerate__parentheses_8cpp_html_gae66f6b31b5ad750f1fe042a706a4e3d4"><div class="ttname"><a href="../../dd/d1e/generate__parentheses_8cpp.html#gae66f6b31b5ad750f1fe042a706a4e3d4">main</a></div><div class="ttdeci">int main()</div><div class="ttdoc">Main function.</div><div class="ttdef"><b>Definition</b> <a href="../../dd/d1e/generate__parentheses_8cpp_source.html#l00110">generate_parentheses.cpp:110</a></div></div>
<div class="ttc" id="ahash__search_8cpp_html_a6e1a77282bc65ad359d753d25df23243"><div class="ttname"><a href="../../d1/df3/hash__search_8cpp.html#a6e1a77282bc65ad359d753d25df23243">data</a></div><div class="ttdeci">int data[MAX]</div><div class="ttdoc">test data</div><div class="ttdef"><b>Definition</b> <a href="../../d1/df3/hash__search_8cpp_source.html#l00024">hash_search.cpp:24</a></div></div>
<div class="ttc" id="astruct_min_heap_node_html"><div class="ttname"><a href="../../d5/d29/struct_min_heap_node.html">MinHeapNode</a></div><div class="ttdef"><b>Definition</b> <a href="#l00007">huffman.cpp:7</a></div></div>
<div class="ttc" id="astructcompare_html"><div class="ttname"><a href="../../d1/db3/structcompare.html">compare</a></div><div class="ttdef"><b>Definition</b> <a href="#l00036">huffman.cpp:36</a></div></div>
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