Merge pull request #52 from Debashis08/feature-graph-implementation

feature: floyd warshall added

Author: Debashis08

Headers/0003_Graph/0013_AllPairsShortestPathsFloydWarshall.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include<vector>
+using namespace std;
+
+namespace AllPairsShortestPathsFloydWarshall
+{
+	class Graph
+	{
+	private:
+		int  _noOfVertices;
+		vector<vector<int>> _adjMatrix;
+		vector<vector<int>> _shortestPathMatrixFloydWarshall;
+		vector<vector<int>> _predecessorMatrix;
+		void InitializeDistanceAndPredecessors();
+		void GetShortestPath(int source, int destination, vector<int>& path);
+		
+	public:
+		void CreateGraph(int noOfVertices);
+		void PushDirectedEdge(int valueU, int valueV, int weight);
+		void FindAllPairsShortestPathsFloydWarshallSolution();
+		vector<vector<int>> GetFloydWarshallShortestPath();
+	};
+}

SourceCodes/0003_Graph/0013_AllPairsShortestPathsFloydWarshall.cc

@@ -0,0 +1,104 @@
+#include "../Headers/0003_Graph/0013_AllPairsShortestPathsFloydWarshall.h"
+#include<climits>
+using namespace std;
+
+namespace AllPairsShortestPathsFloydWarshall
+{
+	// Graph Private Member Methods
+	void Graph::InitializeDistanceAndPredecessors()
+	{
+		this->_shortestPathMatrixFloydWarshall = this->_adjMatrix;
+
+		for (int i = 0; i < this->_noOfVertices; i++)
+		{
+			for (int j = 0; j < this->_noOfVertices; j++)
+			{
+				if ((i == j) || this->_adjMatrix[i][j] == INT_MAX)
+				{
+					this->_predecessorMatrix[i][j] = -1;
+				}
+				else
+				{
+					this->_predecessorMatrix[i][j] = i + 1;
+				}
+			}
+		}
+	}
+
+	void Graph::GetShortestPath(int source, int destination, vector<int>& path)
+	{
+		if (this->_predecessorMatrix[source - 1][destination - 1] != source)
+		{
+			int predecessor = this->_predecessorMatrix[source - 1][destination - 1];
+			this->GetShortestPath(source, predecessor, path);
+			path.push_back(predecessor);
+		}
+	}
+
+	// Graph Public Member Methods
+	void Graph::CreateGraph(int noOfVertices)
+	{
+		this->_noOfVertices = noOfVertices;
+		this->_adjMatrix = vector<vector<int>>(this->_noOfVertices, vector<int>(this->_noOfVertices, INT_MAX));
+		this->_shortestPathMatrixFloydWarshall = vector<vector<int>>(this->_noOfVertices, vector<int>(this->_noOfVertices, INT_MAX));
+		this->_predecessorMatrix = vector<vector<int>>(this->_noOfVertices, vector<int>(this->_noOfVertices, INT_MAX));
+
+		for (int i = 0; i < this->_noOfVertices; i++)
+		{
+			for (int j = 0; j < this->_noOfVertices; j++)
+			{
+				if (i == j)
+				{
+					this->_adjMatrix[i][j] = 0;
+				}
+			}
+		}
+	}
+
+	void Graph::PushDirectedEdge(int valueU, int valueV, int weight)
+	{
+		this->_adjMatrix[valueU - 1][valueV - 1] = weight;
+	}
+
+	void Graph::FindAllPairsShortestPathsFloydWarshallSolution()
+	{
+		this->InitializeDistanceAndPredecessors();
+
+		for (int k = 0; k < this->_noOfVertices; k++)
+		{
+			for (int i = 0; i < this->_noOfVertices; i++)
+			{
+				for (int j = 0; j < this->_noOfVertices; j++)
+				{
+					if ((this->_shortestPathMatrixFloydWarshall[i][j] > (this->_shortestPathMatrixFloydWarshall[i][k] + this->_shortestPathMatrixFloydWarshall[k][j])) 
+						&& 
+						(this->_shortestPathMatrixFloydWarshall[i][k] != INT_MAX && this->_shortestPathMatrixFloydWarshall[k][j] != INT_MAX))
+					{
+						this->_shortestPathMatrixFloydWarshall[i][j] = this->_shortestPathMatrixFloydWarshall[i][k] + this->_shortestPathMatrixFloydWarshall[k][j];
+						this->_predecessorMatrix[i][j] = this->_predecessorMatrix[k][j];
+					}
+				}
+			}
+		}
+	}
+
+	vector<vector<int>> Graph::GetFloydWarshallShortestPath()
+	{
+		vector<vector<int>> result;
+		for (int i = 0; i < this->_noOfVertices; i++)
+		{
+			for (int j = 0; j < this->_noOfVertices; j++)
+			{
+				if (i != j)
+				{
+					vector<int> path = {};
+					path.push_back(i + 1);
+					this->GetShortestPath(i + 1, j + 1, path);
+					path.push_back(j + 1);
+					result.push_back(path);
+				}
+			}
+		}
+		return result;
+	}
+}

SourceCodes/0003_Graph/CMakeLists.txt

@@ -12,6 +12,7 @@ set(0003GRAPH_SOURCES
     0010_DirectedAcyclicGraphShortestPath.cc
     0011_SingleSourceShortestPathDijkstra.cc
     0012_DifferenceConstraintsShortestPaths.cc
+    0013_AllPairsShortestPathsFloydWarshall.cc
 
 )
 

Tests/0003_Graph/0013_AllPairsShortestPathsFloydWarshallTest.cc

@@ -0,0 +1,36 @@
+#include<gtest/gtest.h>
+#include "../Headers/0003_Graph/0013_AllPairsShortestPathsFloydWarshall.h"
+#include"../0000_CommonUtilities/UnitTestHelper.h"
+using namespace std;
+
+namespace AllPairsShortestPathsFloydWarshall
+{
+	UnitTestHelper unitTestHelper;
+
+	TEST(FloydWarshall, SimpleGraph)
+	{
+		// Arrange
+		Graph graph;
+		int noOfVertices = 5;
+		string expectedResult = "[1 5 4 3 2][1 5 4 3][1 5 4][1 5][2 4 1][2 4 3][2 4][2 4 1 5][3 2 4 1][3 2][3 2 4][3 2 4 1 5][4 1][4 3 2][4 3][4 1 5][5 4 1][5 4 3 2][5 4 3][5 4]";
+
+		// Act
+		graph.CreateGraph(noOfVertices);
+
+		graph.PushDirectedEdge(1, 2, 3);
+		graph.PushDirectedEdge(1, 3, 8);
+		graph.PushDirectedEdge(1, 5, -4);
+		graph.PushDirectedEdge(2, 4, 1);
+		graph.PushDirectedEdge(2, 5, 7);
+		graph.PushDirectedEdge(3, 2, 4);
+		graph.PushDirectedEdge(4, 3, -5);
+		graph.PushDirectedEdge(4, 1, 2);
+		graph.PushDirectedEdge(5, 4, 6);
+
+		graph.FindAllPairsShortestPathsFloydWarshallSolution();
+		string actualResult = unitTestHelper.SerializeVectorToString(graph.GetFloydWarshallShortestPath());
+
+		// Assert
+		ASSERT_EQ(actualResult, expectedResult);
+	}
+}

Tests/0003_Graph/CMakeLists.txt

@@ -24,6 +24,7 @@ add_executable(
   0010_DirectedAcyclicGraphShortestPathTest.cc
   0011_SingleSourceShortestPathDijkstraTest.cc
   0012_DifferenceConstraintsShortestPathsTest.cc
+  0013_AllPairsShortestPathsFloydWarshallTest.cc
 )
 
 target_link_libraries(