コード例 #1
0
        /// <summary>
        /// Алгоритм Джонсона. Сложность 0(V^2*lgV + VE), если Фибоначчиевая  куча, или 0(VE*lgV).
        /// Вычисление кратчайших путей между всеми парами вершин
        /// </summary>
        public string JohnsonAlgorithm()
        {
            Size += 1;
            VerticesList.Add(new Vertex(Size));
            Vertex curVertexFrom = VerticesList[Size - 1];

            for (int i = 0; i < Size - 1; i++)
            {
                Vertex       curVertexTo = VerticesList[i];
                IncidentEdge curEdge     = new IncidentEdge(curVertexTo, 0);
                curVertexFrom.AdjacencyList.Add(curEdge);
            }
            if (BellmanFordAlgorithm(curVertexFrom) == false)
            {
                Console.WriteLine("Входной граф содержит цикл с отрицательным весом");
            }
            else
            {
                foreach (var vertex in VerticesList)
                {
                    foreach (var incidentEdge in vertex.AdjacencyList)
                    {
                        incidentEdge.Weight = incidentEdge.Weight + vertex.Distance - incidentEdge.IncidentTo.Distance;
                    }
                }
                VerticesList.RemoveAt(Size - 1);
                Size -= 1;

                int[] Distances = new int[Size];
                for (int i = 0; i < Size; i++)
                {
                    Distances[i] = VerticesList[i].Distance;
                }

                int[,] matrix = new int[Size, Size];
                for (int i = 0; i < Size; i++)
                {
                    Dijkstra(VerticesList[i]);
                    for (int j = 0; j < Size; j++)
                    {
                        matrix[i, j] = VerticesList[j].Distance + Distances[j] - Distances[i];
                    }
                }

                StringBuilder output = new StringBuilder();
                for (int i = 0; i < Size; i++)
                {
                    for (int j = 0; j < Size; j++)
                    {
                        output.Append(matrix[i, j] + " ");
                    }
                    output.Append("\n");
                }
                Console.WriteLine(output);
                return(output.ToString());
            }

            return(null);
        }
コード例 #2
0
        public Graph(int size, string[] strs)
        {
            Size         = size;
            VerticesList = new List <Vertex>();
            for (int i = 1; i <= Size; i++)
            {
                VerticesList.Add(new Vertex(i));
            }

            try
            {
                int curIndex = 0;
                foreach (var str in strs)
                {
                    Vertex curVertexFrom = VerticesList[curIndex];
                    var    array         = str.Split();
                    int    length        = array.Length;
                    if (!string.IsNullOrEmpty(str))
                    {
                        for (int i = 0; i < length; i++)
                        {
                            int intVar = int.Parse(array[i++]);
                            if (intVar > Size)
                            {
                                throw new Exception("The vertex is missing");
                            }
                            Vertex curVertexTo = VerticesList[intVar - 1];

                            intVar = int.Parse(array[i]);
                            IncidentEdge curEdge = new IncidentEdge(curVertexTo, intVar);
                            curVertexFrom.AdjacencyList.Add(curEdge);
                        }
                    }

                    curIndex += 1;
                }
            }
            catch (Exception ex)
            {
                if (ex is NullReferenceException || ex is FormatException)
                {
                    Console.WriteLine("String is empty (Graph)"); //throw new Exception("String is empty (Graph)");
                }
                else
                {
                    throw new Exception(ex.Message);
                }
            }
        }