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<a href="connected__components_8h.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> <span class="comment">// Copyright 2010-2018 Google LLC</span></div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span> <span class="comment">// Licensed under the Apache License, Version 2.0 (the "License");</span></div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span> <span class="comment">// you may not use this file except in compliance with the License.</span></div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span> <span class="comment">// You may obtain a copy of the License at</span></div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span> <span class="comment">//</span></div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span> <span class="comment">// http://www.apache.org/licenses/LICENSE-2.0</span></div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span> <span class="comment">//</span></div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span> <span class="comment">// Unless required by applicable law or agreed to in writing, software</span></div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span> <span class="comment">// distributed under the License is distributed on an "AS IS" BASIS,</span></div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span> <span class="comment">// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span></div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span> <span class="comment">// See the License for the specific language governing permissions and</span></div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span> <span class="comment">// limitations under the License.</span></div><div class="line"><a name="l00013"></a><span class="lineno"> 13</span> </div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span> <span class="comment">//</span></div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span> <span class="comment">// Licensed under the Apache License, Version 2.0 (the "License");</span></div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span> <span class="comment">// you may not use this file except in compliance with the License.</span></div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span> <span class="comment">// You may obtain a copy of the License at</span></div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span> <span class="comment">//</span></div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span> <span class="comment">// http://www.apache.org/licenses/LICENSE-2.0</span></div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span> <span class="comment">//</span></div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span> <span class="comment">// Unless required by applicable law or agreed to in writing, software</span></div><div class="line"><a name="l00022"></a><span class="lineno"> 22</span> <span class="comment">// distributed under the License is distributed on an "AS IS" BASIS,</span></div><div class="line"><a name="l00023"></a><span class="lineno"> 23</span> <span class="comment">// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span></div><div class="line"><a name="l00024"></a><span class="lineno"> 24</span> <span class="comment">// See the License for the specific language governing permissions and</span></div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span> <span class="comment">// limitations under the License.</span></div><div class="line"><a name="l00026"></a><span class="lineno"> 26</span> </div><div class="line"><a name="l00027"></a><span class="lineno"> 27</span> <span class="comment">// Finds the connected components in an undirected graph:</span></div><div class="line"><a name="l00028"></a><span class="lineno"> 28</span> <span class="comment">// https://en.wikipedia.org/wiki/Connected_component_(graph_theory)</span></div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span> <span class="comment">//</span></div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span> <span class="comment">// If you have a fixed graph where the node are dense integers, use</span></div><div class="line"><a name="l00031"></a><span class="lineno"> 31</span> <span class="comment">// GetConnectedComponents(): it's very fast and uses little memory.</span></div><div class="line"><a name="l00032"></a><span class="lineno"> 32</span> <span class="comment">//</span></div><div class="line"><a name="l00033"></a><span class="lineno"> 33</span> <span class="comment">// If you have a more dynamic scenario where you want to incrementally</span></div><div class="line"><a name="l00034"></a><span class="lineno"> 34</span> <span class="comment">// add nodes or edges and query the connectivity between them, use the</span></div><div class="line"><a name="l00035"></a><span class="lineno"> 35</span> <span class="comment">// [Dense]ConnectedComponentsFinder class, which uses the union-find algorithm</span></div><div class="line"><a name="l00036"></a><span class="lineno"> 36</span> <span class="comment">// aka disjoint sets: https://en.wikipedia.org/wiki/Disjoint-set_data_structure.</span></div><div class="line"><a name="l00037"></a><span class="lineno"> 37</span> </div><div class="line"><a name="l00038"></a><span class="lineno"> 38</span> <span class="preprocessor">#ifndef UTIL_GRAPH_CONNECTED_COMPONENTS_H_</span></div><div class="line"><a name="l00039"></a><span class="lineno"> 39</span> <span class="preprocessor">#define UTIL_GRAPH_CONNECTED_COMPONENTS_H_</span></div><div class="line"><a name="l00040"></a><span class="lineno"> 40</span> </div><div class="line"><a name="l00041"></a><span class="lineno"> 41</span> <span class="preprocessor">#include <functional></span></div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span> <span class="preprocessor">#include <map></span></div><div class="line"><a name="l00043"></a><span class="lineno"> 43</span> <span class="preprocessor">#include <memory></span></div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span> <span class="preprocessor">#include <set></span></div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span> <span class="preprocessor">#include <type_traits></span></div><div class="line"><a name="l00046"></a><span class="lineno"> 46</span> <span class="preprocessor">#include <vector></span></div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span> </div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span> <span class="preprocessor">#include "absl/container/flat_hash_map.h"</span></div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span> <span class="preprocessor">#include "absl/container/flat_hash_set.h"</span></div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span> <span class="preprocessor">#include "absl/hash/hash.h"</span></div><div class="line"><a name="l00051"></a><span class="lineno"> 51</span> <span class="preprocessor">#include "absl/meta/type_traits.h"</span></div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span> <span class="preprocessor">#include "ortools/base/logging.h"</span></div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span> <span class="preprocessor">#include "ortools/base/map_util.h"</span></div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span> <span class="preprocessor">#include "ortools/base/ptr_util.h"</span></div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span> </div><div class="line"><a name="l00056"></a><span class="lineno"><a class="line" href="namespaceutil.html"> 56</a></span> <span class="keyword">namespace </span><a class="code" href="namespaceutil.html">util</a> {</div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span> <span class="comment">// Finds the connected components of the graph, using BFS internally.</span></div><div class="line"><a name="l00058"></a><span class="lineno"> 58</span> <span class="comment">// Works on any *undirected* graph class whose nodes are dense integers and that</span></div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span> <span class="comment">// supports the [] operator for adjacency lists: graph[x] must be an integer</span></div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span> <span class="comment">// container listing the nodes that are adjacent to node #x.</span></div><div class="line"><a name="l00061"></a><span class="lineno"> 61</span> <span class="comment">// Example: std::vector<std::vector<int>>.</span></div><div class="line"><a name="l00062"></a><span class="lineno"> 62</span> <span class="comment">//</span></div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span> <span class="comment">// "Undirected" means that for all y in graph[x], x is in graph[y].</span></div><div class="line"><a name="l00064"></a><span class="lineno"> 64</span> <span class="comment">//</span></div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span> <span class="comment">// Returns the mapping from node to component index. The component indices are</span></div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span> <span class="comment">// deterministic: Component #0 will be the one that has node #0, component #1</span></div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span> <span class="comment">// the one that has the lowest-index node that isn't in component #0, and so on.</span></div><div class="line"><a name="l00068"></a><span class="lineno"> 68</span> <span class="comment">//</span></div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span> <span class="comment">// Example on the following 6-node graph: 5--3--0--1 2--4</span></div><div class="line"><a name="l00070"></a><span class="lineno"> 70</span> <span class="comment">// std::vector<std::vector<int>> graph = {{1, 3}, {0}, {4}, {0, 5}, {2}, {3}};</span></div><div class="line"><a name="l00071"></a><span class="lineno"> 71</span> <span class="comment">// GetConnectedComponents(graph); // returns [0, 0, 1, 0, 1, 0].</span></div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span> <span class="keyword">template</span> <<span class="keyword">class</span> UndirectedGraph></div><div class="line"><a name="l00073"></a><span class="lineno"> 73</span> std::vector<int> <a class="code" href="namespaceutil.html#a13f0e8f7e15873600cf8e395958c71e1">GetConnectedComponents</a>(<span class="keywordtype">int</span> num_nodes,</div><div class="line"><a name="l00074"></a><span class="lineno"> 74</span>  <span class="keyword">const</span> UndirectedGraph& graph);</div><div class="line"><a name="l00075"></a><span class="lineno"> 75</span> } <span class="comment">// namespace util</span></div><div class="line"><a name="l00076"></a><span class="lineno"> 76</span> </div><div class="line"><a name="l00077"></a><span class="lineno"> 77</span> <span class="comment">// NOTE(user): The rest of the functions below should also be in namespace</span></div><div class="line"><a name="l00078"></a><span class="lineno"> 78</span> <span class="comment">// util, but for historical reasons it hasn't been done yet.</span></div><div class="line"><a name="l00079"></a><span class="lineno"> 79</span> </div><div class="line"><a name="l00080"></a><span class="lineno"> 80</span> <span class="comment">// A connected components finder that only works on dense ints.</span></div><div class="line"><a name="l00081"></a><span class="lineno"><a class="line" href="classDenseConnectedComponentsFinder.html"> 81</a></span> <span class="keyword">class </span><a class="code" href="classDenseConnectedComponentsFinder.html">DenseConnectedComponentsFinder</a> {</div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span>  <span class="keyword">public</span>:</div><div class="line"><a name="l00083"></a><span class="lineno"><a class="line" href="classDenseConnectedComponentsFinder.html#a33639c91528c2a525e1591df24ff2cc9"> 83</a></span>  <a class="code" href="classDenseConnectedComponentsFinder.html#a33639c91528c2a525e1591df24ff2cc9">DenseConnectedComponentsFinder</a>() {}</div><div class="line"><a name="l00084"></a><span class="lineno"> 84</span> </div><div class="line"><a name="l00085"></a><span class="lineno"> 85</span>  <a class="code" href="classDenseConnectedComponentsFinder.html#a33639c91528c2a525e1591df24ff2cc9">DenseConnectedComponentsFinder</a>(<span class="keyword">const</span> <a class="code" href="classDenseConnectedComponentsFinder.html">DenseConnectedComponentsFinder</a>&) =</div><div class="line"><a name="l00086"></a><span class="lineno"> 86</span>  <span class="keyword">delete</span>;</div><div class="line"><a name="l00087"></a><span class="lineno"> 87</span>  <a class="code" href="classDenseConnectedComponentsFinder.html">DenseConnectedComponentsFinder</a>& <a class="code" href="classDenseConnectedComponentsFinder.html#a20f2a5d6bb7631a0dcdd678387a1b61a">operator=</a>(</div><div class="line"><a name="l00088"></a><span class="lineno"> 88</span>  <span class="keyword">const</span> <a class="code" href="classDenseConnectedComponentsFinder.html">DenseConnectedComponentsFinder</a>&) = <span class="keyword">delete</span>;</div><div class="line"><a name="l00089"></a><span class="lineno"> 89</span> </div><div class="line"><a name="l00090"></a><span class="lineno"> 90</span>  <span class="comment">// The main API is the same as ConnectedComponentsFinder (below): see the</span></div><div class="line"><a name="l00091"></a><span class="lineno"> 91</span>  <span class="comment">// homonymous functions there.</span></div><div class="line"><a name="l00092"></a><span class="lineno"> 92</span>  <span class="keywordtype">void</span> <a class="code" href="classDenseConnectedComponentsFinder.html#aba450cf3f16d9386d043c4354a19a4aa">AddEdge</a>(<span class="keywordtype">int</span> node1, <span class="keywordtype">int</span> node2);</div><div class="line"><a name="l00093"></a><span class="lineno"> 93</span>  <span class="keywordtype">bool</span> <a class="code" href="classDenseConnectedComponentsFinder.html#a071f52956431e211e14ed7f3894c1d0b">Connected</a>(<span class="keywordtype">int</span> node1, <span class="keywordtype">int</span> node2);</div><div class="line"><a name="l00094"></a><span class="lineno"> 94</span>  <span class="keywordtype">int</span> <a class="code" href="classDenseConnectedComponentsFinder.html#a0a639b64de57bc14f04f0f238e0092d1">GetSize</a>(<span class="keywordtype">int</span> node);</div><div class="line"><a name="l00095"></a><span class="lineno"><a class="line" href="classDenseConnectedComponentsFinder.html#a5090a0bdc205d23778d2b8a742f5c5fd"> 95</a></span>  <span class="keywordtype">int</span> <a class="code" href="classDenseConnectedComponentsFinder.html#a5090a0bdc205d23778d2b8a742f5c5fd">GetNumberOfComponents</a>()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> num_components_; }</div><div class="line"><a name="l00096"></a><span class="lineno"><a class="line" href="classDenseConnectedComponentsFinder.html#a317fb43e59ef01ebe3d0d492b4ab33dd"> 96</a></span>  <span class="keywordtype">int</span> <a class="code" href="classDenseConnectedComponentsFinder.html#a317fb43e59ef01ebe3d0d492b4ab33dd">GetNumberOfNodes</a>()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> parent_.size(); }</div><div class="line"><a name="l00097"></a><span class="lineno"> 97</span> </div><div class="line"><a name="l00098"></a><span class="lineno"> 98</span>  <span class="comment">// Sets the number of nodes in the graph. The graph can only grow: this</span></div><div class="line"><a name="l00099"></a><span class="lineno"> 99</span>  <span class="comment">// dies if "num_nodes" is lower or equal to any of the values ever given</span></div><div class="line"><a name="l00100"></a><span class="lineno"> 100</span>  <span class="comment">// to AddEdge(), or lower than a previous value given to SetNumberOfNodes().</span></div><div class="line"><a name="l00101"></a><span class="lineno"> 101</span>  <span class="comment">// You need this if there are nodes that don't have any edges.</span></div><div class="line"><a name="l00102"></a><span class="lineno"> 102</span>  <span class="keywordtype">void</span> <a class="code" href="classDenseConnectedComponentsFinder.html#a46780e194c525fa9853fa899d69b4340">SetNumberOfNodes</a>(<span class="keywordtype">int</span> num_nodes);</div><div class="line"><a name="l00103"></a><span class="lineno"> 103</span> </div><div class="line"><a name="l00104"></a><span class="lineno"> 104</span>  <span class="comment">// Returns the root of the set for the given node. node must be in</span></div><div class="line"><a name="l00105"></a><span class="lineno"> 105</span>  <span class="comment">// [0;GetNumberOfNodes()-1].</span></div><div class="line"><a name="l00106"></a><span class="lineno"> 106</span>  <span class="comment">// Non-const because it does path compression internally.</span></div><div class="line"><a name="l00107"></a><span class="lineno"> 107</span>  <span class="keywordtype">int</span> <a class="code" href="classDenseConnectedComponentsFinder.html#afdcff89dd2374ce33c05934d328e64ec">FindRoot</a>(<span class="keywordtype">int</span> node);</div><div class="line"><a name="l00108"></a><span class="lineno"> 108</span> </div><div class="line"><a name="l00109"></a><span class="lineno"> 109</span>  <span class="comment">// Returns the same as GetConnectedComponents().</span></div><div class="line"><a name="l00110"></a><span class="lineno"> 110</span>  std::vector<int> <a class="code" href="classDenseConnectedComponentsFinder.html#aee7f0057f42256a520b5ef32bae58b36">GetComponentIds</a>();</div><div class="line"><a name="l00111"></a><span class="lineno"> 111</span> </div><div class="line"><a name="l00112"></a><span class="lineno"> 112</span>  <span class="keyword">private</span>:</div><div class="line"><a name="l00113"></a><span class="lineno"> 113</span>  <span class="comment">// parent[i] is the id of an ancestor for node i. A node is a root iff</span></div><div class="line"><a name="l00114"></a><span class="lineno"> 114</span>  <span class="comment">// parent[i] == i.</span></div><div class="line"><a name="l00115"></a><span class="lineno"> 115</span>  std::vector<int> parent_;</div><div class="line"><a name="l00116"></a><span class="lineno"> 116</span>  <span class="comment">// If i is a root, component_size_[i] is the number of elements in the</span></div><div class="line"><a name="l00117"></a><span class="lineno"> 117</span>  <span class="comment">// component. If i is not a root, component_size_[i] is meaningless.</span></div><div class="line"><a name="l00118"></a><span class="lineno"> 118</span>  std::vector<int> component_size_;</div><div class="line"><a name="l00119"></a><span class="lineno"> 119</span>  <span class="comment">// rank[i] is the depth of the tree.</span></div><div class="line"><a name="l00120"></a><span class="lineno"> 120</span>  std::vector<int> rank_;</div><div class="line"><a name="l00121"></a><span class="lineno"> 121</span>  <span class="comment">// Number of connected components.</span></div><div class="line"><a name="l00122"></a><span class="lineno"> 122</span>  <span class="keywordtype">int</span> num_components_ = 0;</div><div class="line"><a name="l00123"></a><span class="lineno"> 123</span> };</div><div class="line"><a name="l00124"></a><span class="lineno"> 124</span> </div><div class="line"><a name="l00125"></a><span class="lineno"> 125</span> <span class="keyword">namespace </span>internal {</div><div class="line"><a name="l00126"></a><span class="lineno"> 126</span> <span class="comment">// A helper to deduce the type of map to use depending on whether CompareOrHashT</span></div><div class="line"><a name="l00127"></a><span class="lineno"> 127</span> <span class="comment">// is a comparator or a hasher (prefer the latter).</span></div><div class="line"><a name="l00128"></a><span class="lineno"> 128</span> <span class="keyword">template</span> <<span class="keyword">typename</span> T, <span class="keyword">typename</span> CompareOrHashT></div><div class="line"><a name="l00129"></a><span class="lineno"> 129</span> <span class="keyword">struct </span>ConnectedComponentsTypeHelper {</div><div class="line"><a name="l00130"></a><span class="lineno"> 130</span>  <span class="comment">// SFINAE trait to detect hash functors and select unordered containers if so,</span></div><div class="line"><a name="l00131"></a><span class="lineno"> 131</span>  <span class="comment">// and ordered containers otherwise (= by default).</span></div><div class="line"><a name="l00132"></a><span class="lineno"> 132</span>  <span class="keyword">template</span> <<span class="keyword">typename</span> U, <span class="keyword">typename</span> E = <span class="keywordtype">void</span>></div><div class="line"><a name="l00133"></a><span class="lineno"> 133</span>  <span class="keyword">struct </span>SelectContainer {</div><div class="line"><a name="l00134"></a><span class="lineno"> 134</span>  <span class="keyword">using</span> Set = std::set<T, CompareOrHashT>;</div><div class="line"><a name="l00135"></a><span class="lineno"> 135</span>  <span class="keyword">using</span> Map = std::map<T, int, CompareOrHashT>;</div><div class="line"><a name="l00136"></a><span class="lineno"> 136</span>  };</div><div class="line"><a name="l00137"></a><span class="lineno"> 137</span> </div><div class="line"><a name="l00138"></a><span class="lineno"> 138</span>  <span class="comment">// The expression inside decltype is basically saying that "H(x)" is</span></div><div class="line"><a name="l00139"></a><span class="lineno"> 139</span>  <span class="comment">// well-formed, where H is an instance of U and x is an instance of T, and is</span></div><div class="line"><a name="l00140"></a><span class="lineno"> 140</span>  <span class="comment">// a value of integral type. That is, we are "duck-typing" on whether U looks</span></div><div class="line"><a name="l00141"></a><span class="lineno"> 141</span>  <span class="comment">// like a hash functor.</span></div><div class="line"><a name="l00142"></a><span class="lineno"> 142</span>  <span class="keyword">template</span> <<span class="keyword">typename</span> U></div><div class="line"><a name="l00143"></a><span class="lineno"> 143</span>  <span class="keyword">struct </span>SelectContainer<</div><div class="line"><a name="l00144"></a><span class="lineno"> 144</span>  U, absl::enable_if_t<std::is_integral<decltype(</div><div class="line"><a name="l00145"></a><span class="lineno"> 145</span>  std::declval<const U&>()(std::declval<const T&>()))>::value>> {</div><div class="line"><a name="l00146"></a><span class="lineno"> 146</span>  <span class="keyword">using</span> Set = absl::flat_hash_set<T, CompareOrHashT>;</div><div class="line"><a name="l00147"></a><span class="lineno"> 147</span>  <span class="keyword">using</span> Map = absl::flat_hash_map<T, int, CompareOrHashT>;</div><div class="line"><a name="l00148"></a><span class="lineno"> 148</span>  };</div><div class="line"><a name="l00149"></a><span class="lineno"> 149</span> </div><div class="line"><a name="l00150"></a><span class="lineno"> 150</span>  <span class="keyword">using</span> Set = <span class="keyword">typename</span> SelectContainer<CompareOrHashT>::Set;</div><div class="line"><a name="l00151"></a><span class="lineno"> 151</span>  <span class="keyword">using</span> Map = <span class="keyword">typename</span> SelectContainer<CompareOrHashT>::Map;</div><div class="line"><a name="l00152"></a><span class="lineno"> 152</span> };</div><div class="line"><a name="l00153"></a><span class="lineno"> 153</span> </div><div class="line"><a name="l00154"></a><span class="lineno"> 154</span> } <span class="comment">// namespace internal</span></div><div class="line"><a name="l00155"></a><span class="lineno"> 155</span> </div><div class="line"><a name="l00156"></a><span class="lineno"> 156</span> <span class="comment">// Usage:</span></div><div class="line"><a name="l00157"></a><span class="lineno"> 157</span> <span class="comment">// ConnectedComponentsFinder<MyNodeType> cc;</span></div><div class="line"><a name="l00158"></a><span class="lineno"> 158</span> <span class="comment">// cc.AddNode(node1);</span></div><div class="line"><a name="l00159"></a><span class="lineno"> 159</span> <span class="comment">// cc.AddNode(node2);</span></div><div class="line"><a name="l00160"></a><span class="lineno"> 160</span> <span class="comment">// cc.AddEdge(node1, node2);</span></div><div class="line"><a name="l00161"></a><span class="lineno"> 161</span> <span class="comment">// ... repeating, adding nodes and edges as needed. Adding an edge</span></div><div class="line"><a name="l00162"></a><span class="lineno"> 162</span> <span class="comment">// will automatically also add the two nodes at its ends, if they</span></div><div class="line"><a name="l00163"></a><span class="lineno"> 163</span> <span class="comment">// haven't already been added.</span></div><div class="line"><a name="l00164"></a><span class="lineno"> 164</span> <span class="comment">// std::vector<std::set<MyNodeType> > components;</span></div><div class="line"><a name="l00165"></a><span class="lineno"> 165</span> <span class="comment">// cc.FindConnectedComponents(&components);</span></div><div class="line"><a name="l00166"></a><span class="lineno"> 166</span> <span class="comment">// Each entry in components now contains all the nodes in a single</span></div><div class="line"><a name="l00167"></a><span class="lineno"> 167</span> <span class="comment">// connected component.</span></div><div class="line"><a name="l00168"></a><span class="lineno"> 168</span> <span class="comment">//</span></div><div class="line"><a name="l00169"></a><span class="lineno"> 169</span> <span class="comment">// Usage with flat_hash_set:</span></div><div class="line"><a name="l00170"></a><span class="lineno"> 170</span> <span class="comment">// using ConnectedComponentType = flat_hash_set<MyNodeType>;</span></div><div class="line"><a name="l00171"></a><span class="lineno"> 171</span> <span class="comment">// ConnectedComponentsFinder<ConnectedComponentType::key_type,</span></div><div class="line"><a name="l00172"></a><span class="lineno"> 172</span> <span class="comment">// ConnectedComponentType::hasher></span></div><div class="line"><a name="l00173"></a><span class="lineno"> 173</span> <span class="comment">// cc;</span></div><div class="line"><a name="l00174"></a><span class="lineno"> 174</span> <span class="comment">// ...</span></div><div class="line"><a name="l00175"></a><span class="lineno"> 175</span> <span class="comment">// std::vector<ConnectedComponentType> components;</span></div><div class="line"><a name="l00176"></a><span class="lineno"> 176</span> <span class="comment">// cc.FindConnectedComponents(&components);</span></div><div class="line"><a name="l00177"></a><span class="lineno"> 177</span> <span class="comment">//</span></div><div class="line"><a name="l00178"></a><span class="lineno"> 178</span> <span class="comment">// If you want to, you can continue adding nodes and edges after calling</span></div><div class="line"><a name="l00179"></a><span class="lineno"> 179</span> <span class="comment">// FindConnectedComponents, then call it again later.</span></div><div class="line"><a name="l00180"></a><span class="lineno"> 180</span> <span class="comment">//</span></div><div class="line"><a name="l00181"></a><span class="lineno"> 181</span> <span class="comment">// If your node type isn't STL-friendly, then you can use pointers to</span></div><div class="line"><a name="l00182"></a><span class="lineno"> 182</span> <span class="comment">// it instead:</span></div><div class="line"><a name="l00183"></a><span class="lineno"> 183</span> <span class="comment">// ConnectedComponentsFinder<MySTLUnfriendlyNodeType*> cc;</span></div><div class="line"><a name="l00184"></a><span class="lineno"> 184</span> <span class="comment">// cc.AddNode(&node1);</span></div><div class="line"><a name="l00185"></a><span class="lineno"> 185</span> <span class="comment">// ... and so on...</span></div><div class="line"><a name="l00186"></a><span class="lineno"> 186</span> <span class="comment">// Of course, in this usage, the connected components finder retains</span></div><div class="line"><a name="l00187"></a><span class="lineno"> 187</span> <span class="comment">// these pointers through its lifetime (though it doesn't dereference them).</span></div><div class="line"><a name="l00188"></a><span class="lineno"> 188</span> <span class="keyword">template</span> <<span class="keyword">typename</span> T, <span class="keyword">typename</span> CompareOrHashT = std::less<T>></div><div class="line"><a name="l00189"></a><span class="lineno"><a class="line" href="classConnectedComponentsFinder.html"> 189</a></span> <span class="keyword">class </span><a class="code" href="classConnectedComponentsFinder.html">ConnectedComponentsFinder</a> {</div><div class="line"><a name="l00190"></a><span class="lineno"> 190</span>  <span class="keyword">public</span>:</div><div class="line"><a name="l00191"></a><span class="lineno"> 191</span>  <span class="comment">// Constructs a connected components finder.</span></div><div class="line"><a name="l00192"></a><span class="lineno"><a class="line" href="classConnectedComponentsFinder.html#aa669a113d3ee23c506b97949f740b1cc"> 192</a></span>  <a class="code" href="classConnectedComponentsFinder.html#aa669a113d3ee23c506b97949f740b1cc">ConnectedComponentsFinder</a>() {}</div><div class="line"><a name="l00193"></a><span class="lineno"> 193</span> </div><div class="line"><a name="l00194"></a><span class="lineno"> 194</span>  <a class="code" href="classConnectedComponentsFinder.html#aa669a113d3ee23c506b97949f740b1cc">ConnectedComponentsFinder</a>(<span class="keyword">const</span> <a class="code" href="classConnectedComponentsFinder.html">ConnectedComponentsFinder</a>&) = <span class="keyword">delete</span>;</div><div class="line"><a name="l00195"></a><span class="lineno"> 195</span>  <a class="code" href="classConnectedComponentsFinder.html">ConnectedComponentsFinder</a>& <a class="code" href="classConnectedComponentsFinder.html#a21da7363443c34ad00c529fae4b3b3e2">operator=</a>(<span class="keyword">const</span> <a class="code" href="classConnectedComponentsFinder.html">ConnectedComponentsFinder</a>&) =</div><div class="line"><a name="l00196"></a><span class="lineno"> 196</span>  <span class="keyword">delete</span>;</div><div class="line"><a name="l00197"></a><span class="lineno"> 197</span> </div><div class="line"><a name="l00198"></a><span class="lineno"> 198</span>  <span class="comment">// Adds a node in the graph. It is OK to add the same node more than</span></div><div class="line"><a name="l00199"></a><span class="lineno"> 199</span>  <span class="comment">// once; additions after the first have no effect.</span></div><div class="line"><a name="l00200"></a><span class="lineno"><a class="line" href="classConnectedComponentsFinder.html#a93b2c753675c77bfdbc0c33eb582380b"> 200</a></span>  <span class="keywordtype">void</span> <a class="code" href="classConnectedComponentsFinder.html#a93b2c753675c77bfdbc0c33eb582380b">AddNode</a>(T node) { LookupOrInsertNode<true>(node); }</div><div class="line"><a name="l00201"></a><span class="lineno"> 201</span> </div><div class="line"><a name="l00202"></a><span class="lineno"> 202</span>  <span class="comment">// Adds an edge in the graph. Also adds both endpoint nodes as necessary.</span></div><div class="line"><a name="l00203"></a><span class="lineno"> 203</span>  <span class="comment">// It is not an error to add the same edge twice. Self-edges are OK too.</span></div><div class="line"><a name="l00204"></a><span class="lineno"><a class="line" href="classConnectedComponentsFinder.html#a77a24beaed190e2f3a0d12662a65b18a"> 204</a></span>  <span class="keywordtype">void</span> <a class="code" href="classConnectedComponentsFinder.html#a77a24beaed190e2f3a0d12662a65b18a">AddEdge</a>(T node1, T node2) {</div><div class="line"><a name="l00205"></a><span class="lineno"> 205</span>  delegate_.<a class="code" href="classDenseConnectedComponentsFinder.html#aba450cf3f16d9386d043c4354a19a4aa">AddEdge</a>(LookupOrInsertNode<false>(node1),</div><div class="line"><a name="l00206"></a><span class="lineno"> 206</span>  LookupOrInsertNode<false>(node2));</div><div class="line"><a name="l00207"></a><span class="lineno"> 207</span>  }</div><div class="line"><a name="l00208"></a><span class="lineno"> 208</span> </div><div class="line"><a name="l00209"></a><span class="lineno"> 209</span>  <span class="comment">// Returns true iff both nodes are in the same connected component.</span></div><div class="line"><a name="l00210"></a><span class="lineno"> 210</span>  <span class="comment">// Returns false if either node has not been already added with AddNode.</span></div><div class="line"><a name="l00211"></a><span class="lineno"><a class="line" href="classConnectedComponentsFinder.html#a67dc34888511ab5b90b7389c90dbc1f8"> 211</a></span>  <span class="keywordtype">bool</span> <a class="code" href="classConnectedComponentsFinder.html#a67dc34888511ab5b90b7389c90dbc1f8">Connected</a>(T node1, T node2) {</div><div class="line"><a name="l00212"></a><span class="lineno"> 212</span>  <span class="keywordflow">return</span> delegate_.<a class="code" href="classDenseConnectedComponentsFinder.html#a071f52956431e211e14ed7f3894c1d0b">Connected</a>(gtl::FindWithDefault(index_, node1, -1),</div><div class="line"><a name="l00213"></a><span class="lineno"> 213</span>  gtl::FindWithDefault(index_, node2, -1));</div><div class="line"><a name="l00214"></a><span class="lineno"> 214</span>  }</div><div class="line"><a name="l00215"></a><span class="lineno"> 215</span> </div><div class="line"><a name="l00216"></a><span class="lineno"> 216</span>  <span class="comment">// Finds the connected component containing a node, and returns the</span></div><div class="line"><a name="l00217"></a><span class="lineno"> 217</span>  <span class="comment">// total number of nodes in that component. Returns zero iff the</span></div><div class="line"><a name="l00218"></a><span class="lineno"> 218</span>  <span class="comment">// node has not been already added with AddNode.</span></div><div class="line"><a name="l00219"></a><span class="lineno"><a class="line" href="classConnectedComponentsFinder.html#a7a173636e3dce11a27f2f7121e01a563"> 219</a></span>  <span class="keywordtype">int</span> <a class="code" href="classConnectedComponentsFinder.html#a7a173636e3dce11a27f2f7121e01a563">GetSize</a>(T node) {</div><div class="line"><a name="l00220"></a><span class="lineno"> 220</span>  <span class="keywordflow">return</span> delegate_.<a class="code" href="classDenseConnectedComponentsFinder.html#a0a639b64de57bc14f04f0f238e0092d1">GetSize</a>(gtl::FindWithDefault(index_, node, -1));</div><div class="line"><a name="l00221"></a><span class="lineno"> 221</span>  }</div><div class="line"><a name="l00222"></a><span class="lineno"> 222</span> </div><div class="line"><a name="l00223"></a><span class="lineno"> 223</span>  <span class="comment">// Finds all the connected components and assigns them to components.</span></div><div class="line"><a name="l00224"></a><span class="lineno"> 224</span>  <span class="comment">// Components are ordered in the same way nodes were added, i.e. if node 'b'</span></div><div class="line"><a name="l00225"></a><span class="lineno"> 225</span>  <span class="comment">// was added before node 'c', then either:</span></div><div class="line"><a name="l00226"></a><span class="lineno"> 226</span>  <span class="comment">// - 'c' belongs to the same component as a node 'a' added before 'b', or</span></div><div class="line"><a name="l00227"></a><span class="lineno"> 227</span>  <span class="comment">// - the component for 'c' comes after the one for 'b'.</span></div><div class="line"><a name="l00228"></a><span class="lineno"> 228</span>  <span class="comment">// There are two versions:</span></div><div class="line"><a name="l00229"></a><span class="lineno"> 229</span>  <span class="comment">// - The first one returns the result, and stores each component in a vector.</span></div><div class="line"><a name="l00230"></a><span class="lineno"> 230</span>  <span class="comment">// This is the preferred version.</span></div><div class="line"><a name="l00231"></a><span class="lineno"> 231</span>  <span class="comment">// - The second one populates the result, and stores each component in a set.</span></div><div class="line"><a name="l00232"></a><span class="lineno"><a class="line" href="classConnectedComponentsFinder.html#a9eaa06cffceda90c1d44f550ad3459f3"> 232</a></span>  std::vector<std::vector<T>> <a class="code" href="classConnectedComponentsFinder.html#a9eaa06cffceda90c1d44f550ad3459f3">FindConnectedComponents</a>() {</div><div class="line"><a name="l00233"></a><span class="lineno"> 233</span>  <span class="keyword">const</span> <span class="keyword">auto</span> component_ids = delegate_.<a class="code" href="classDenseConnectedComponentsFinder.html#aee7f0057f42256a520b5ef32bae58b36">GetComponentIds</a>();</div><div class="line"><a name="l00234"></a><span class="lineno"> 234</span>  std::vector<std::vector<T>> components(delegate_.<a class="code" href="classDenseConnectedComponentsFinder.html#a5090a0bdc205d23778d2b8a742f5c5fd">GetNumberOfComponents</a>());</div><div class="line"><a name="l00235"></a><span class="lineno"> 235</span>  <span class="keywordflow">for</span> (<span class="keyword">const</span> <span class="keyword">auto</span>& elem_id : index_) {</div><div class="line"><a name="l00236"></a><span class="lineno"> 236</span>  components[component_ids[elem_id.second]].push_back(elem_id.first);</div><div class="line"><a name="l00237"></a><span class="lineno"> 237</span>  }</div><div class="line"><a name="l00238"></a><span class="lineno"> 238</span>  <span class="keywordflow">return</span> components;</div><div class="line"><a name="l00239"></a><span class="lineno"> 239</span>  }</div><div class="line"><a name="l00240"></a><span class="lineno"><a class="line" href="classConnectedComponentsFinder.html#a7f7b2f745e4c87bcaafec8fa295bfa91"> 240</a></span>  <span class="keywordtype">void</span> <a class="code" href="classConnectedComponentsFinder.html#a7f7b2f745e4c87bcaafec8fa295bfa91">FindConnectedComponents</a>(</div><div class="line"><a name="l00241"></a><span class="lineno"> 241</span>  std::vector<<span class="keyword">typename</span> internal::ConnectedComponentsTypeHelper<</div><div class="line"><a name="l00242"></a><span class="lineno"> 242</span>  T, CompareOrHashT>::Set>* components) {</div><div class="line"><a name="l00243"></a><span class="lineno"> 243</span>  <span class="keyword">const</span> <span class="keyword">auto</span> component_ids = delegate_.<a class="code" href="classDenseConnectedComponentsFinder.html#aee7f0057f42256a520b5ef32bae58b36">GetComponentIds</a>();</div><div class="line"><a name="l00244"></a><span class="lineno"> 244</span>  components->clear();</div><div class="line"><a name="l00245"></a><span class="lineno"> 245</span>  components->resize(delegate_.<a class="code" href="classDenseConnectedComponentsFinder.html#a5090a0bdc205d23778d2b8a742f5c5fd">GetNumberOfComponents</a>());</div><div class="line"><a name="l00246"></a><span class="lineno"> 246</span>  <span class="keywordflow">for</span> (<span class="keyword">const</span> <span class="keyword">auto</span>& elem_id : index_) {</div><div class="line"><a name="l00247"></a><span class="lineno"> 247</span>  components->at(component_ids[elem_id.second]).insert(elem_id.first);</div><div class="line"><a name="l00248"></a><span class="lineno"> 248</span>  }</div><div class="line"><a name="l00249"></a><span class="lineno"> 249</span>  }</div><div class="line"><a name="l00250"></a><span class="lineno"> 250</span> </div><div class="line"><a name="l00251"></a><span class="lineno"> 251</span>  <span class="comment">// Returns the current number of connected components.</span></div><div class="line"><a name="l00252"></a><span class="lineno"> 252</span>  <span class="comment">// This number can change as the new nodes or edges are added.</span></div><div class="line"><a name="l00253"></a><span class="lineno"><a class="line" href="classConnectedComponentsFinder.html#a30350bb98f0e1f7ae47ec1292d253b52"> 253</a></span>  <span class="keywordtype">int</span> <a class="code" href="classConnectedComponentsFinder.html#a30350bb98f0e1f7ae47ec1292d253b52">GetNumberOfComponents</a>()<span class="keyword"> const </span>{</div><div class="line"><a name="l00254"></a><span class="lineno"> 254</span>  <span class="keywordflow">return</span> delegate_.<a class="code" href="classDenseConnectedComponentsFinder.html#a5090a0bdc205d23778d2b8a742f5c5fd">GetNumberOfComponents</a>();</div><div class="line"><a name="l00255"></a><span class="lineno"> 255</span>  }</div><div class="line"><a name="l00256"></a><span class="lineno"> 256</span> </div><div class="line"><a name="l00257"></a><span class="lineno"> 257</span>  <span class="comment">// Returns the current number of added distinct nodes.</span></div><div class="line"><a name="l00258"></a><span class="lineno"> 258</span>  <span class="comment">// This includes nodes added explicitly via the calls to AddNode() method</span></div><div class="line"><a name="l00259"></a><span class="lineno"> 259</span>  <span class="comment">// and implicitly via the calls to AddEdge() method.</span></div><div class="line"><a name="l00260"></a><span class="lineno"> 260</span>  <span class="comment">// Nodes that were added several times only count once.</span></div><div class="line"><a name="l00261"></a><span class="lineno"><a class="line" href="classConnectedComponentsFinder.html#a350a0a0790e558f619478ce97c8f2ae7"> 261</a></span>  <span class="keywordtype">int</span> <a class="code" href="classConnectedComponentsFinder.html#a350a0a0790e558f619478ce97c8f2ae7">GetNumberOfNodes</a>()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> delegate_.<a class="code" href="classDenseConnectedComponentsFinder.html#a317fb43e59ef01ebe3d0d492b4ab33dd">GetNumberOfNodes</a>(); }</div><div class="line"><a name="l00262"></a><span class="lineno"> 262</span> </div><div class="line"><a name="l00263"></a><span class="lineno"> 263</span>  <span class="keyword">private</span>:</div><div class="line"><a name="l00264"></a><span class="lineno"> 264</span>  <span class="comment">// Returns the index for the given node. If the node does not exist and</span></div><div class="line"><a name="l00265"></a><span class="lineno"> 265</span>  <span class="comment">// update_delegate is true, explicitly add the node to the delegate.</span></div><div class="line"><a name="l00266"></a><span class="lineno"> 266</span>  <span class="keyword">template</span> <<span class="keywordtype">bool</span> update_delegate></div><div class="line"><a name="l00267"></a><span class="lineno"> 267</span>  <span class="keywordtype">int</span> LookupOrInsertNode(T node) {</div><div class="line"><a name="l00268"></a><span class="lineno"> 268</span>  <span class="keyword">const</span> <span class="keyword">auto</span> result = index_.emplace(node, index_.size());</div><div class="line"><a name="l00269"></a><span class="lineno"> 269</span>  <span class="keyword">const</span> <span class="keywordtype">int</span> node_id = result.first->second;</div><div class="line"><a name="l00270"></a><span class="lineno"> 270</span>  <span class="keywordflow">if</span> (update_delegate && result.second) {</div><div class="line"><a name="l00271"></a><span class="lineno"> 271</span>  <span class="comment">// A new index was created.</span></div><div class="line"><a name="l00272"></a><span class="lineno"> 272</span>  delegate_.<a class="code" href="classDenseConnectedComponentsFinder.html#a46780e194c525fa9853fa899d69b4340">SetNumberOfNodes</a>(node_id + 1);</div><div class="line"><a name="l00273"></a><span class="lineno"> 273</span>  }</div><div class="line"><a name="l00274"></a><span class="lineno"> 274</span>  <span class="keywordflow">return</span> node_id;</div><div class="line"><a name="l00275"></a><span class="lineno"> 275</span>  }</div><div class="line"><a name="l00276"></a><span class="lineno"> 276</span> </div><div class="line"><a name="l00277"></a><span class="lineno"> 277</span>  <a class="code" href="classDenseConnectedComponentsFinder.html">DenseConnectedComponentsFinder</a> delegate_;</div><div class="line"><a name="l00278"></a><span class="lineno"> 278</span>  <span class="keyword">typename</span> internal::ConnectedComponentsTypeHelper<T, CompareOrHashT>::Map</div><div class="line"><a name="l00279"></a><span class="lineno"> 279</span>  index_;</div><div class="line"><a name="l00280"></a><span class="lineno"> 280</span> };</div><div class="line"><a name="l00281"></a><span class="lineno"> 281</span> </div><div class="line"><a name="l00282"></a><span class="lineno"> 282</span> <span class="comment">// =============================================================================</span></div><div class="line"><a name="l00283"></a><span class="lineno"> 283</span> <span class="comment">// Implementations of the method templates</span></div><div class="line"><a name="l00284"></a><span class="lineno"> 284</span> <span class="comment">// =============================================================================</span></div><div class="line"><a name="l00285"></a><span class="lineno"> 285</span> <span class="keyword">namespace </span><a class="code" href="namespaceutil.html">util</a> {</div><div class="line"><a name="l00286"></a><span class="lineno"> 286</span> <span class="keyword">template</span> <<span class="keyword">class</span> UndirectedGraph></div><div class="line"><a name="l00287"></a><span class="lineno"> 287</span> std::vector<int> <a class="code" href="namespaceutil.html#a13f0e8f7e15873600cf8e395958c71e1">GetConnectedComponents</a>(<span class="keywordtype">int</span> num_nodes,</div><div class="line"><a name="l00288"></a><span class="lineno"> 288</span>  <span class="keyword">const</span> UndirectedGraph& graph) {</div><div class="line"><a name="l00289"></a><span class="lineno"><a class="line" href="namespaceutil.html#a13f0e8f7e15873600cf8e395958c71e1"> 289</a></span>  std::vector<int> component_of_node(num_nodes, -1);</div><div class="line"><a name="l00290"></a><span class="lineno"> 290</span>  std::vector<int> bfs_queue;</div><div class="line"><a name="l00291"></a><span class="lineno"> 291</span>  <span class="keywordtype">int</span> num_components = 0;</div><div class="line"><a name="l00292"></a><span class="lineno"> 292</span>  <span class="keywordflow">for</span> (<span class="keywordtype">int</span> src = 0; src < num_nodes; ++src) {</div><div class="line"><a name="l00293"></a><span class="lineno"> 293</span>  <span class="keywordflow">if</span> (component_of_node[src] >= 0) <span class="keywordflow">continue</span>;</div><div class="line"><a name="l00294"></a><span class="lineno"> 294</span>  bfs_queue.push_back(src);</div><div class="line"><a name="l00295"></a><span class="lineno"> 295</span>  component_of_node[src] = num_components;</div><div class="line"><a name="l00296"></a><span class="lineno"> 296</span>  <span class="keywordflow">for</span> (<span class="keywordtype">int</span> num_visited = 0; num_visited < bfs_queue.size(); ++num_visited) {</div><div class="line"><a name="l00297"></a><span class="lineno"> 297</span>  <span class="keyword">const</span> <span class="keywordtype">int</span> node = bfs_queue[num_visited];</div><div class="line"><a name="l00298"></a><span class="lineno"> 298</span>  <span class="keywordflow">for</span> (<span class="keyword">const</span> <span class="keywordtype">int</span> neighbor : graph[node]) {</div><div class="line"><a name="l00299"></a><span class="lineno"> 299</span>  <span class="keywordflow">if</span> (component_of_node[neighbor] >= 0) <span class="keywordflow">continue</span>;</div><div class="line"><a name="l00300"></a><span class="lineno"> 300</span>  component_of_node[neighbor] = num_components;</div><div class="line"><a name="l00301"></a><span class="lineno"> 301</span>  bfs_queue.push_back(neighbor);</div><div class="line"><a name="l00302"></a><span class="lineno"> 302</span>  }</div><div class="line"><a name="l00303"></a><span class="lineno"> 303</span>  }</div><div class="line"><a name="l00304"></a><span class="lineno"> 304</span>  ++num_components;</div><div class="line"><a name="l00305"></a><span class="lineno"> 305</span>  bfs_queue.clear();</div><div class="line"><a name="l00306"></a><span class="lineno"> 306</span>  }</div><div class="line"><a name="l00307"></a><span class="lineno"> 307</span>  <span class="keywordflow">return</span> component_of_node;</div><div class="line"><a name="l00308"></a><span class="lineno"> 308</span> }</div><div class="line"><a name="l00309"></a><span class="lineno"> 309</span> } <span class="comment">// namespace util</span></div><div class="line"><a name="l00310"></a><span class="lineno"> 310</span> </div><div class="line"><a name="l00311"></a><span class="lineno"> 311</span> <span class="preprocessor">#endif // UTIL_GRAPH_CONNECTED_COMPONENTS_H_</span></div><div class="ttc" id="classConnectedComponentsFinder_html_a77a24beaed190e2f3a0d12662a65b18a"><div class="ttname"><a href="classConnectedComponentsFinder.html#a77a24beaed190e2f3a0d12662a65b18a">ConnectedComponentsFinder::AddEdge</a></div><div class="ttdeci">void AddEdge(T node1, T node2)</div><div class="ttdoc">Adds an edge in the graph.</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00204">connected_components.h:204</a></div></div>
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<div class="ttc" id="classConnectedComponentsFinder_html_a93b2c753675c77bfdbc0c33eb582380b"><div class="ttname"><a href="classConnectedComponentsFinder.html#a93b2c753675c77bfdbc0c33eb582380b">ConnectedComponentsFinder::AddNode</a></div><div class="ttdeci">void AddNode(T node)</div><div class="ttdoc">Adds a node in the graph.</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00200">connected_components.h:200</a></div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html_a071f52956431e211e14ed7f3894c1d0b"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html#a071f52956431e211e14ed7f3894c1d0b">DenseConnectedComponentsFinder::Connected</a></div><div class="ttdeci">bool Connected(int node1, int node2)</div></div>
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<div class="ttc" id="namespaceutil_html"><div class="ttname"><a href="namespaceutil.html">util</a></div><div class="ttdoc">Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in c...</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00056">connected_components.h:56</a></div></div>
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<div class="ttc" id="classConnectedComponentsFinder_html_aa669a113d3ee23c506b97949f740b1cc"><div class="ttname"><a href="classConnectedComponentsFinder.html#aa669a113d3ee23c506b97949f740b1cc">ConnectedComponentsFinder::ConnectedComponentsFinder</a></div><div class="ttdeci">ConnectedComponentsFinder()</div><div class="ttdoc">Constructs a connected components finder.</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00192">connected_components.h:192</a></div></div>
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<div class="ttc" id="classConnectedComponentsFinder_html_a7a173636e3dce11a27f2f7121e01a563"><div class="ttname"><a href="classConnectedComponentsFinder.html#a7a173636e3dce11a27f2f7121e01a563">ConnectedComponentsFinder::GetSize</a></div><div class="ttdeci">int GetSize(T node)</div><div class="ttdoc">Finds the connected component containing a node, and returns the total number of nodes in that compon...</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00219">connected_components.h:219</a></div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html_a46780e194c525fa9853fa899d69b4340"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html#a46780e194c525fa9853fa899d69b4340">DenseConnectedComponentsFinder::SetNumberOfNodes</a></div><div class="ttdeci">void SetNumberOfNodes(int num_nodes)</div><div class="ttdoc">Sets the number of nodes in the graph.</div></div>
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<div class="ttc" id="classConnectedComponentsFinder_html_a9eaa06cffceda90c1d44f550ad3459f3"><div class="ttname"><a href="classConnectedComponentsFinder.html#a9eaa06cffceda90c1d44f550ad3459f3">ConnectedComponentsFinder::FindConnectedComponents</a></div><div class="ttdeci">std::vector< std::vector< T > > FindConnectedComponents()</div><div class="ttdoc">Finds all the connected components and assigns them to components.</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00232">connected_components.h:232</a></div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html_a33639c91528c2a525e1591df24ff2cc9"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html#a33639c91528c2a525e1591df24ff2cc9">DenseConnectedComponentsFinder::DenseConnectedComponentsFinder</a></div><div class="ttdeci">DenseConnectedComponentsFinder()</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00083">connected_components.h:83</a></div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html">DenseConnectedComponentsFinder</a></div><div class="ttdoc">NOTE(user): The rest of the functions below should also be in namespace util, but for historical reas...</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00081">connected_components.h:81</a></div></div>
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<div class="ttc" id="namespaceutil_html_a13f0e8f7e15873600cf8e395958c71e1"><div class="ttname"><a href="namespaceutil.html#a13f0e8f7e15873600cf8e395958c71e1">util::GetConnectedComponents</a></div><div class="ttdeci">std::vector< int > GetConnectedComponents(int num_nodes, const UndirectedGraph &graph)</div><div class="ttdoc">Finds the connected components of the graph, using BFS internally.</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00289">connected_components.h:289</a></div></div>
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<div class="ttc" id="classConnectedComponentsFinder_html_a350a0a0790e558f619478ce97c8f2ae7"><div class="ttname"><a href="classConnectedComponentsFinder.html#a350a0a0790e558f619478ce97c8f2ae7">ConnectedComponentsFinder::GetNumberOfNodes</a></div><div class="ttdeci">int GetNumberOfNodes() const</div><div class="ttdoc">Returns the current number of added distinct nodes.</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00261">connected_components.h:261</a></div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html_a317fb43e59ef01ebe3d0d492b4ab33dd"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html#a317fb43e59ef01ebe3d0d492b4ab33dd">DenseConnectedComponentsFinder::GetNumberOfNodes</a></div><div class="ttdeci">int GetNumberOfNodes() const</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00096">connected_components.h:96</a></div></div>
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<div class="ttc" id="classConnectedComponentsFinder_html_a67dc34888511ab5b90b7389c90dbc1f8"><div class="ttname"><a href="classConnectedComponentsFinder.html#a67dc34888511ab5b90b7389c90dbc1f8">ConnectedComponentsFinder::Connected</a></div><div class="ttdeci">bool Connected(T node1, T node2)</div><div class="ttdoc">Returns true iff both nodes are in the same connected component.</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00211">connected_components.h:211</a></div></div>
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<div class="ttc" id="classConnectedComponentsFinder_html_a30350bb98f0e1f7ae47ec1292d253b52"><div class="ttname"><a href="classConnectedComponentsFinder.html#a30350bb98f0e1f7ae47ec1292d253b52">ConnectedComponentsFinder::GetNumberOfComponents</a></div><div class="ttdeci">int GetNumberOfComponents() const</div><div class="ttdoc">Returns the current number of connected components.</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00253">connected_components.h:253</a></div></div>
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<div class="ttc" id="classConnectedComponentsFinder_html_a21da7363443c34ad00c529fae4b3b3e2"><div class="ttname"><a href="classConnectedComponentsFinder.html#a21da7363443c34ad00c529fae4b3b3e2">ConnectedComponentsFinder::operator=</a></div><div class="ttdeci">ConnectedComponentsFinder & operator=(const ConnectedComponentsFinder &)=delete</div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html_a5090a0bdc205d23778d2b8a742f5c5fd"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html#a5090a0bdc205d23778d2b8a742f5c5fd">DenseConnectedComponentsFinder::GetNumberOfComponents</a></div><div class="ttdeci">int GetNumberOfComponents() const</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00095">connected_components.h:95</a></div></div>
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<div class="ttc" id="classConnectedComponentsFinder_html"><div class="ttname"><a href="classConnectedComponentsFinder.html">ConnectedComponentsFinder</a></div><div class="ttdoc">Usage: ConnectedComponentsFinder<MyNodeType> cc; cc.AddNode(node1); cc.AddNode(node2); cc....</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00189">connected_components.h:189</a></div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html_a0a639b64de57bc14f04f0f238e0092d1"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html#a0a639b64de57bc14f04f0f238e0092d1">DenseConnectedComponentsFinder::GetSize</a></div><div class="ttdeci">int GetSize(int node)</div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html_aee7f0057f42256a520b5ef32bae58b36"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html#aee7f0057f42256a520b5ef32bae58b36">DenseConnectedComponentsFinder::GetComponentIds</a></div><div class="ttdeci">std::vector< int > GetComponentIds()</div><div class="ttdoc">Returns the same as GetConnectedComponents().</div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html_a20f2a5d6bb7631a0dcdd678387a1b61a"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html#a20f2a5d6bb7631a0dcdd678387a1b61a">DenseConnectedComponentsFinder::operator=</a></div><div class="ttdeci">DenseConnectedComponentsFinder & operator=(const DenseConnectedComponentsFinder &)=delete</div></div>
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<div class="ttc" id="classConnectedComponentsFinder_html_a7f7b2f745e4c87bcaafec8fa295bfa91"><div class="ttname"><a href="classConnectedComponentsFinder.html#a7f7b2f745e4c87bcaafec8fa295bfa91">ConnectedComponentsFinder::FindConnectedComponents</a></div><div class="ttdeci">void FindConnectedComponents(std::vector< typename internal::ConnectedComponentsTypeHelper< T, CompareOrHashT >::Set > *components)</div><div class="ttdef"><b>Definition:</b> <a href="connected__components_8h_source.html#l00240">connected_components.h:240</a></div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html_aba450cf3f16d9386d043c4354a19a4aa"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html#aba450cf3f16d9386d043c4354a19a4aa">DenseConnectedComponentsFinder::AddEdge</a></div><div class="ttdeci">void AddEdge(int node1, int node2)</div><div class="ttdoc">The main API is the same as ConnectedComponentsFinder (below): see the homonymous functions there.</div></div>
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<div class="ttc" id="classDenseConnectedComponentsFinder_html_afdcff89dd2374ce33c05934d328e64ec"><div class="ttname"><a href="classDenseConnectedComponentsFinder.html#afdcff89dd2374ce33c05934d328e64ec">DenseConnectedComponentsFinder::FindRoot</a></div><div class="ttdeci">int FindRoot(int node)</div><div class="ttdoc">Returns the root of the set for the given node.</div></div>
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