Bron kerbosch (#467)

* Bron Kerbosch implementation. No pivots. Needs more tests. * More tests added. Need a few more. * Added another test case. * Formatted relevant files to pass clang-format checks
ZigRazor · Oct 7, 2024 · 6284c8b · 6284c8b
1 parent c747d80
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Showing 9 changed files with 271 additions and 5 deletions.
diff --git a/include/CXXGraph/Graph/Algorithm/BestFirstSearch_impl.hpp b/include/CXXGraph/Graph/Algorithm/BestFirstSearch_impl.hpp
@@ -22,12 +22,12 @@
 
 #pragma once
 
+#include <algorithm>
 #include <atomic>
 #include <condition_variable>
 #include <mutex>
 #include <queue>
 #include <thread>
-#include <algorithm>
 
 #include "CXXGraph/Graph/Graph_decl.h"
 

diff --git a/include/CXXGraph/Graph/Algorithm/BronKerbosch_impl.hpp b/include/CXXGraph/Graph/Algorithm/BronKerbosch_impl.hpp
@@ -0,0 +1,75 @@
+/***********************************************************/
+/***      ______  ____  ______                 _         ***/
+/***     / ___\ \/ /\ \/ / ___|_ __ __ _ _ __ | |__	     ***/
+/***    | |    \  /  \  / |  _| '__/ _` | '_ \| '_ \	 ***/
+/***    | |___ /  \  /  \ |_| | | | (_| | |_) | | | |    ***/
+/***     \____/_/\_\/_/\_\____|_|  \__,_| .__/|_| |_|    ***/
+/***                                    |_|			     ***/
+/***********************************************************/
+/***     Header-Only C++ Library for Graph			     ***/
+/***	 Representation and Algorithms				     ***/
+/***********************************************************/
+/***     Author: ZigRazor ***/
+/***	 E-Mail: zigrazor@gmail.com 				     ***/
+/***********************************************************/
+/***	 Collaboration: ----------- 				     ***/
+/***********************************************************/
+/***	 License: AGPL v3.0 ***/
+/***********************************************************/
+
+#ifndef __CXXGRAPH_BRONKERBOSCH_IMPL_H__
+#define __CXXGRAPH_BRONKERBOSCH_IMPL_H__
+
+#pragma once
+
+#include "CXXGraph/Graph/Graph_decl.h"
+
+namespace CXXGraph {
+
+template <typename T>
+const BronKerboschResult<T> Graph<T>::bron_kerbosch() const {
+  std::vector<T_NodeSet<T>> maximalCliques{};
+  BronKerboschResult<T> result;
+
+  if (!isUndirectedGraph()) {
+    result.success = false;
+    result.errorMessage = ERR_DIR_GRAPH;
+    return result;
+  }
+
+  T_NodeSet<T> _X, _R, _P(getNodeSet());
+
+  std::function<void(T_NodeSet<T>, T_NodeSet<T>, T_NodeSet<T>)> rec =
+      [&maximalCliques, &rec, this](T_NodeSet<T> R, T_NodeSet<T> P,
+                                    T_NodeSet<T> X) {
+        if (P.empty() && X.empty()) {
+          maximalCliques.push_back(R);
+        }
+
+        auto it = P.begin();
+        while (it != P.end()) {
+          const auto v = *it;
+          T_NodeSet<T> X2, R2(R), P2, nbd(inOutNeighbors(v));
+          R2.insert(v);
+          for (const auto &u : nbd) {
+            if (X.count(u) > 0 && u != v) {
+              X2.insert(u);
+            }
+            if (P.count(u) > 0 && u != v) {
+              P2.insert(u);
+            }
+          }
+          rec(R2, P2, X2);
+          X.insert(v);
+          it = P.erase(it);
+        }
+      };
+
+  rec(_R, _P, _X);
+  result.success = true;
+  result.maximalCliques = maximalCliques;
+  return result;
+}
+
+}  // namespace CXXGraph
+#endif
diff --git a/include/CXXGraph/Graph/Algorithm/Dijkstra_impl.hpp b/include/CXXGraph/Graph/Algorithm/Dijkstra_impl.hpp
@@ -52,7 +52,7 @@ const DijkstraResult Graph<T>::dijkstra(const Node<T>& source,
   }
   // n denotes the number of vertices in graph
   // unused
-  //auto n = cachedAdjMatrix->size();
+  // auto n = cachedAdjMatrix->size();
 
   // setting all the distances initially to INF_DOUBLE
   std::unordered_map<shared<const Node<T>>, double, nodeHash<T>> dist;
@@ -177,7 +177,7 @@ const DijkstraResult Graph<T>::dijkstra_deterministic(
   }
   // n denotes the number of vertices in graph
   // unused
-  //auto n = cachedAdjMatrix->size();
+  // auto n = cachedAdjMatrix->size();
 
   // setting all the distances initially to INF_DOUBLE
   std::unordered_map<shared<const Node<T>>, double, nodeHash<T>> dist;

diff --git a/include/CXXGraph/Graph/Graph.h b/include/CXXGraph/Graph/Graph.h
@@ -27,6 +27,7 @@
 #include "CXXGraph/Graph/Algorithm/BestFirstSearch_impl.hpp"
 #include "CXXGraph/Graph/Algorithm/Boruvka_impl.hpp"
 #include "CXXGraph/Graph/Algorithm/BreadthFirstSearch_impl.hpp"
+#include "CXXGraph/Graph/Algorithm/BronKerbosch_impl.hpp"
 #include "CXXGraph/Graph/Algorithm/Connectivity_impl.hpp"
 #include "CXXGraph/Graph/Algorithm/CycleDetection_impl.hpp"
 #include "CXXGraph/Graph/Algorithm/DepthFirstSearch_impl.hpp"

diff --git a/include/CXXGraph/Graph/Graph_decl.h b/include/CXXGraph/Graph/Graph_decl.h
@@ -663,7 +663,7 @@ class Graph {
    * mst: vector containing id of nodes in minimum spanning tree & cost of MST
    * mstCost: Cost of MST
    * errorMessage: "" if no error ELSE report the encountered error
-   */	
+   */
   virtual const MstResult boruvka_deterministic() const;
 
   /**
@@ -703,6 +703,9 @@ class Graph {
    * search.
    *
    */
+
+  virtual const BronKerboschResult<T> bron_kerbosch() const;
+
   virtual const std::vector<Node<T>> breadth_first_search(
       const Node<T> &start) const;
 

diff --git a/include/CXXGraph/Graph/Graph_impl.hpp b/include/CXXGraph/Graph/Graph_impl.hpp
@@ -22,8 +22,8 @@
 
 #pragma once
 
-#include <deque>
 #include <algorithm>
+#include <deque>
 
 #include "CXXGraph/Graph/Graph_decl.h"
 #include "CXXGraph/Utility/ConstString.hpp"

diff --git a/include/CXXGraph/Utility/Typedef.hpp b/include/CXXGraph/Utility/Typedef.hpp
@@ -237,6 +237,17 @@ struct BestFirstSearchResult_struct {
 template <typename T>
 using BestFirstSearchResult = BestFirstSearchResult_struct<T>;
 
+// Struct that contains information about BronKerbosch algorithm results
+template <typename T>
+struct BronKerboschResult_struct {
+  bool success = false;
+  std::string errorMessage = "";
+  std::vector<std::unordered_set<shared<const Node<T>>, nodeHash<T>>>
+      maximalCliques = {};
+};
+template <typename T>
+using BronKerboschResult = BronKerboschResult_struct<T>;
+
 ///////////////////////////////////////////////////////////////////////////////////
 // Using Definition
 // ///////////////////////////////////////////////////////////////

diff --git a/test/BronKerboschTest.cpp b/test/BronKerboschTest.cpp
@@ -0,0 +1,175 @@
+#include <memory>
+
+#include "CXXGraph/CXXGraph.hpp"
+#include "gtest/gtest.h"
+
+// Smart pointers alias
+template <typename T>
+using unique = std::unique_ptr<T>;
+template <typename T>
+using shared = std::shared_ptr<T>;
+
+using std::make_shared;
+using std::make_unique;
+
+TEST(BronKerboschTest, test_1) {
+  CXXGraph::Node<int> node0("0", 0);
+  CXXGraph::Node<int> node1("1", 1);
+  CXXGraph::Node<int> node2("2", 2);
+  CXXGraph::Node<int> node3("3", 3);
+  CXXGraph::Node<int> node4("4", 4);
+
+  CXXGraph::UndirectedEdge<int> edge0(0, node0, node1);
+  CXXGraph::UndirectedEdge<int> edge1(0, node0, node2);
+  CXXGraph::UndirectedEdge<int> edge2(0, node2, node1);
+  CXXGraph::UndirectedEdge<int> edge3(0, node2, node3);
+  CXXGraph::UndirectedEdge<int> edge4(0, node2, node4);
+  CXXGraph::UndirectedEdge<int> edge5(0, node3, node4);
+
+  CXXGraph::T_EdgeSet<int> edgeSet;
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge0));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge1));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge2));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge3));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge4));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge5));
+
+  CXXGraph::Graph<int> graph(edgeSet);
+  CXXGraph::BronKerboschResult<int> res = graph.bron_kerbosch();
+
+  ASSERT_TRUE(res.success);
+  ASSERT_EQ(res.maximalCliques.size(), 2);
+  ASSERT_EQ(res.errorMessage, "");
+  ASSERT_TRUE(std::find(res.maximalCliques.begin(), res.maximalCliques.end(),
+                        CXXGraph::T_NodeSet<int>{
+                            make_shared<CXXGraph::Node<int>>(node0),
+                            make_shared<CXXGraph::Node<int>>(node1),
+                            make_shared<CXXGraph::Node<int>>(node2)}) !=
+              res.maximalCliques.end());
+  ASSERT_TRUE(std::find(res.maximalCliques.begin(), res.maximalCliques.end(),
+                        CXXGraph::T_NodeSet<int>{
+                            make_shared<CXXGraph::Node<int>>(node2),
+                            make_shared<CXXGraph::Node<int>>(node3),
+                            make_shared<CXXGraph::Node<int>>(node4)}) !=
+              res.maximalCliques.end());
+}
+
+// Empty graph E_5
+TEST(BronKerboschTest, test_2) {
+  CXXGraph::Node<int> node0("0", 0);
+  CXXGraph::Node<int> node1("1", 1);
+  CXXGraph::Node<int> node2("2", 2);
+  CXXGraph::Node<int> node3("3", 3);
+  CXXGraph::Node<int> node4("4", 4);
+
+  CXXGraph::T_EdgeSet<int> edgeSet;
+  CXXGraph::Graph<int> graph(edgeSet);
+
+  graph.addNode(&node0);
+  graph.addNode(&node1);
+  graph.addNode(&node2);
+  graph.addNode(&node3);
+  graph.addNode(&node4);
+
+  CXXGraph::BronKerboschResult<int> res = graph.bron_kerbosch();
+  ASSERT_TRUE(res.success);
+  ASSERT_EQ(res.maximalCliques.size(), 5);
+  ASSERT_EQ(res.errorMessage, "");
+  ASSERT_TRUE(std::find(res.maximalCliques.begin(), res.maximalCliques.end(),
+                        CXXGraph::T_NodeSet<int>{
+                            make_shared<CXXGraph::Node<int>>(node0)}) !=
+              res.maximalCliques.end());
+  ASSERT_TRUE(std::find(res.maximalCliques.begin(), res.maximalCliques.end(),
+                        CXXGraph::T_NodeSet<int>{
+                            make_shared<CXXGraph::Node<int>>(node1)}) !=
+              res.maximalCliques.end());
+  ASSERT_TRUE(std::find(res.maximalCliques.begin(), res.maximalCliques.end(),
+                        CXXGraph::T_NodeSet<int>{
+                            make_shared<CXXGraph::Node<int>>(node2)}) !=
+              res.maximalCliques.end());
+  ASSERT_TRUE(std::find(res.maximalCliques.begin(), res.maximalCliques.end(),
+                        CXXGraph::T_NodeSet<int>{
+                            make_shared<CXXGraph::Node<int>>(node3)}) !=
+              res.maximalCliques.end());
+  ASSERT_TRUE(std::find(res.maximalCliques.begin(), res.maximalCliques.end(),
+                        CXXGraph::T_NodeSet<int>{
+                            make_shared<CXXGraph::Node<int>>(node4)}) !=
+              res.maximalCliques.end());
+}
+
+// Complete graph K_5
+TEST(BronKerboschTest, test_3) {
+  CXXGraph::Node<int> node0("0", 0);
+  CXXGraph::Node<int> node1("1", 1);
+  CXXGraph::Node<int> node2("2", 2);
+  CXXGraph::Node<int> node3("3", 3);
+  CXXGraph::Node<int> node4("4", 4);
+
+  CXXGraph::UndirectedEdge<int> edge0(0, node0, node1);
+  CXXGraph::UndirectedEdge<int> edge1(1, node0, node2);
+  CXXGraph::UndirectedEdge<int> edge2(2, node0, node3);
+  CXXGraph::UndirectedEdge<int> edge3(3, node0, node4);
+  CXXGraph::UndirectedEdge<int> edge4(4, node1, node2);
+  CXXGraph::UndirectedEdge<int> edge5(5, node1, node3);
+  CXXGraph::UndirectedEdge<int> edge6(6, node1, node4);
+  CXXGraph::UndirectedEdge<int> edge7(7, node2, node3);
+  CXXGraph::UndirectedEdge<int> edge8(8, node2, node4);
+  CXXGraph::UndirectedEdge<int> edge9(9, node3, node4);
+
+  CXXGraph::T_EdgeSet<int> edgeSet;
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge0));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge1));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge2));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge3));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge4));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge5));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge6));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge7));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge8));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge9));
+
+  CXXGraph::Graph<int> graph(edgeSet);
+  CXXGraph::BronKerboschResult<int> res = graph.bron_kerbosch();
+
+  ASSERT_TRUE(res.success);
+  ASSERT_EQ(res.maximalCliques.size(), 1);
+  ASSERT_EQ(res.errorMessage, "");
+  ASSERT_TRUE(std::find(res.maximalCliques.begin(), res.maximalCliques.end(),
+                        CXXGraph::T_NodeSet<int>{
+                            make_shared<CXXGraph::Node<int>>(node0),
+                            make_shared<CXXGraph::Node<int>>(node1),
+                            make_shared<CXXGraph::Node<int>>(node2),
+                            make_shared<CXXGraph::Node<int>>(node3),
+                            make_shared<CXXGraph::Node<int>>(node4)}) !=
+              res.maximalCliques.end());
+}
+
+// Graph with a directed edge
+TEST(BronKerboschTest, test_4) {
+  CXXGraph::Node<int> node0("0", 0);
+  CXXGraph::Node<int> node1("1", 1);
+  CXXGraph::Node<int> node2("2", 2);
+  CXXGraph::Node<int> node3("3", 3);
+  CXXGraph::Node<int> node4("4", 4);
+
+  CXXGraph::DirectedEdge<int> edge0(0, node0, node1);
+  CXXGraph::UndirectedEdge<int> edge1(0, node0, node2);
+  CXXGraph::UndirectedEdge<int> edge2(0, node2, node1);
+  CXXGraph::UndirectedEdge<int> edge3(0, node2, node3);
+  CXXGraph::UndirectedEdge<int> edge4(0, node2, node4);
+  CXXGraph::UndirectedEdge<int> edge5(0, node3, node4);
+
+  CXXGraph::T_EdgeSet<int> edgeSet;
+  edgeSet.insert(make_shared<CXXGraph::DirectedEdge<int>>(edge0));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge1));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge2));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge3));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge4));
+  edgeSet.insert(make_shared<CXXGraph::UndirectedEdge<int>>(edge5));
+
+  CXXGraph::Graph<int> graph(edgeSet);
+  CXXGraph::BronKerboschResult<int> res = graph.bron_kerbosch();
+
+  ASSERT_FALSE(res.success);
+  ASSERT_EQ(res.errorMessage, "Graph is directed");
+}
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
@@ -89,6 +89,7 @@ if(TEST)
 
     add_test(test_bellmanford test_exe --gtest_filter=BellmanFord*)
     add_test(test_boruvka test_exe --gtest_filter=Boruvka*)
+    add_test(test_bron_kerbosch test_exe --gtest_filter=BronKerbosch*)
     add_test(test_connectivity test_exe --gtest_filter=Connectivity*)
     add_test(test_euler_path test_exe --gtest_filter=EulerPath*)
     add_test(test_fordfulkerson test_exe --gtest_filter=FordFulkerson*)