fixed some errors in the scc logic

Author: Debashis08

Headers/0003_Graph/0004_StronglyConnectedComponents.h

@@ -26,14 +26,14 @@ class StronglyConnectedComponentsGraph
     map<SCCNode*, list<SCCNode*>> _adjlistT;
     map<int, SCCNode*> _nodeMap;
     list<SCCNode*> _nodesFinishingTimeOrder;
-    vector<vector<SCCNode*>> _allConnectedComponents;
+    vector<vector<int>> _allConnectedComponents;
     SCCNode* MakeOrFindNode(int value);
     void DepthFirstSearchOnGraphG(SCCNode* DFSNode);
-    vector<SCCNode*> DepthFirstSearchOnGraphT(SCCNode* DFSNode, vector<SCCNode*> connectedComponents);
+    vector<int> DepthFirstSearchOnGraphT(SCCNode* DFSNode, vector<int> connectedComponents);
 public:
     void PushDirectedEdge(int valueU, int valueV);
     void PushSingleNode(int valueU);
     void DFSOnGraphG();
     void DFSOnGraphT();
-    void FindAllStronglyConnectedComponents();
+    vector<vector<int>> FindAllStronglyConnectedComponents();
 };

SourceCodes/0003_Graph/0004_StronglyConnectedComponents.cc

@@ -47,10 +47,11 @@ void StronglyConnectedComponentsGraph::DepthFirstSearchOnGraphG(SCCNode* nodeU)
 	this->_nodesFinishingTimeOrder.push_front(nodeU);
 }
 
-vector<SCCNode*> StronglyConnectedComponentsGraph::DepthFirstSearchOnGraphT(SCCNode* nodeU, vector<SCCNode*> connectedComponents)
+vector<int> StronglyConnectedComponentsGraph::DepthFirstSearchOnGraphT(SCCNode* nodeU, vector<int> connectedComponents)
 {
 	nodeU->color = GRAY;
-	for (auto nodeV : this->_adjlistG[nodeU])
+	connectedComponents.push_back(nodeU->data);
+	for (auto nodeV : this->_adjlistT[nodeU])
 	{
 		if (nodeV->color == WHITE)
 		{
@@ -71,7 +72,7 @@ void StronglyConnectedComponentsGraph::PushDirectedEdge(int valueU, int valueV)
 	this->_adjlistG[nodeU].push_back(nodeV);
 
 	// Creating the transpose of the actual graph.
-	this->_adjlistG[nodeV].push_back(nodeU);
+	this->_adjlistT[nodeV].push_back(nodeU);
 }
 
 void StronglyConnectedComponentsGraph::PushSingleNode(int valueU)
@@ -103,15 +104,16 @@ void StronglyConnectedComponentsGraph::DFSOnGraphT()
 	{
 		if (iterator->color == WHITE)
 		{
-			vector<SCCNode*> connectedComponents;
+			vector<int> connectedComponents;
 			auto result = this->DepthFirstSearchOnGraphT(iterator, connectedComponents);
 			this->_allConnectedComponents.push_back(result);
 		}
 	}
 }
 
-
-void StronglyConnectedComponentsGraph::FindAllStronglyConnectedComponents()
+vector<vector<int>> StronglyConnectedComponentsGraph::FindAllStronglyConnectedComponents()
 {
 	this->DFSOnGraphG();
+	this->DFSOnGraphT();
+	return this->_allConnectedComponents;
 }

Tests/0000_CommonUtilities/UnitTestHelper.h

@@ -51,4 +51,20 @@ class UnitTestHelper
 		}
 		return result;
 	}
+
+	template<typename T>
+	string VerifyVectorResult(vector<vector<T>> vector)
+	{
+		string result = "";
+		for (auto& iterator : vector)
+		{
+			result += "[";
+			for (auto& it : iterator)
+			{
+				result += to_string(it) + " ";
+			}
+			result += "]";
+		}
+		return result;
+	}
 };

Tests/0003_Graph/0004_StronglyConnectedComponentsTest.cc

@@ -0,0 +1,32 @@
+#include<gtest/gtest.h>
+#include "../Headers/0003_Graph/0004_StronglyConnectedComponents.h"
+#include "../0000_CommonUtilities/UnitTestHelper.h"
+
+namespace StronglyConnectedComponentsTest
+{
+	UnitTestHelper  unitTestHelper;
+
+	TEST(StronglyConnectedComponentsTesting, SimpleGraphTest)
+	{
+		StronglyConnectedComponentsGraph graph;
+
+		graph.PushDirectedEdge(1, 2);
+		graph.PushDirectedEdge(2, 3);
+		graph.PushDirectedEdge(2, 5);
+		graph.PushDirectedEdge(2, 6);
+		graph.PushDirectedEdge(3, 4);
+		graph.PushDirectedEdge(3, 7);
+		graph.PushDirectedEdge(4, 3);
+		graph.PushDirectedEdge(4, 8);
+		graph.PushDirectedEdge(5, 1);
+		graph.PushDirectedEdge(5, 6);
+		graph.PushDirectedEdge(6, 7);
+		graph.PushDirectedEdge(7, 6);
+		graph.PushDirectedEdge(7, 8);
+		graph.PushDirectedEdge(8, 8);
+
+		string actualResult = unitTestHelper.VerifyVectorResult(graph.FindAllStronglyConnectedComponents());
+		string expectedResult = "";
+		EXPECT_EQ(actualResult, expectedResult);
+	}
+}