Esempio n. 1
0
        public static void FordFulkerson(DrawingSurface ds)
        {
            if (ds.IsUndirected())
            {
                var err = new ErrorBox("Graph have to be directed!");
                err.ShowDialog();
                return;
            }

            if (ds.ContainsNegativeEdge())
            {
                var err = new ErrorBox("Graph can not contain negative edges!");
                err.ShowDialog();
                return;
            }

            Dictionary <int, List <Edge> > adjList = ds.GetDestAdjList();

            (var source, var sink) = GetSourceAndSink(adjList);

            if (source == -1 || sink == -1)
            {
                var err = new ErrorBox("Graph have to contain source and sink!");
                err.ShowDialog();
                return;
            }
            ;

            var fulkersonItems = new FulkersonItem[adjList.Count, adjList.Count];
            var minimalFlow    = .0;
            var flows          = new List <double>();

            msg.MoveToCorner(ds.FindForm() as Form1);
            msg.SetTitle("Ford-Fulkerson algorithm result:\n");
            msg.StartMenu();

            for (var i = 0; i < adjList.Count; ++i)
            {
                for (var j = 0; j < adjList.Count; ++j)
                {
                    fulkersonItems[i, j] = new FulkersonItem();
                }
            }

            for (var start = 0; start < adjList.Count; ++start)
            {
                foreach (var edge in adjList[start])
                {
                    fulkersonItems[start, edge.end].toFlow = edge.w;
                    edge.SetLabel($"{edge.w}/{0}");
                }
            }

            while (minimalFlow != -1)
            {
                ds.Vertices[source].fillColor = Color.Green;
                ds.Vertices[sink].fillColor   = Color.Red;
                ds.Invalidate();
                minimalFlow = ProcessFulkerson(source, sink, adjList, ref fulkersonItems, ds);
                if (minimalFlow != -1)
                {
                    flows.Add(minimalFlow);
                }
                ClearVertices(ds);
                ClearEdges(ds, false);
            }
            AlgorithmDone(ds);
            msg.AddText($"Total maximal flow:\n");
            msg.AddText("f(G) = ");

            for (var i = 0; i < flows.Count; ++i)
            {
                msg.AddText($"{flows[i]} ");
                if (i != flows.Count - 1)
                {
                    msg.AddText("+ ");
                }
                Thread.Sleep(700);
            }
            msg.AddText($"= {flows.Sum()}");
            msg.WaitOne();
            ClearVertices(ds);
            ClearEdges(ds, true);
        }
Esempio n. 2
0
        public static void Dijkstra(DrawingSurface ds, int start)
        {
            if (ds.ContainsNegativeEdge())
            {
                var err = new ErrorBox("Graph contains negative edges");
                err.ShowDialog();
                return;
            }

            Dictionary <int, List <Edge> > adjList = ds.GetDestAdjList();
            var que = new C5.IntervalHeap <Edge>(new EdgeCompare());

            double[] dist             = Enumerable.Repeat((double)int.MaxValue, adjList.Count).ToArray();
            int[]    parent           = Enumerable.Repeat(-1, adjList.Count).ToArray();
            var      visitedColor     = Color.Green;
            var      processedColor   = Color.Yellow;
            var      currentEdgeColor = Color.Red;

            que.Add(new Edge(ds.Vertices[start], ds.Vertices[start], 0, true));
            dist[start] = 0;

            for (var i = 0; i < ds.Vertices.Count; ++i)
            {
                ds.Vertices[i].label = "INF";
            }
            ds.Vertices[start].label = "0";

            while (que.Count != 0)
            {
                var currEdge    = que.FindMin(); que.DeleteMin();
                var startVertex = (ds.Vertices[currEdge.end].fillColor == visitedColor) ? currEdge.start : currEdge.end;
                ReDrawCircle(ds, startVertex, visitedColor);

                foreach (var edge in adjList[startVertex])
                {
                    var currVertex = (edge.end != startVertex) ? edge.end : edge.start;
                    ReDrawEdge(ds, edge, currentEdgeColor, 300);

                    if (ds.Vertices[currVertex].fillColor != visitedColor)
                    {
                        ReDrawCircle(ds, currVertex, processedColor, 0);
                    }
                    Thread.Sleep(1000);
                    if (dist[currVertex] > dist[startVertex] + edge.w)
                    {
                        dist[currVertex]              = dist[startVertex] + edge.w;
                        parent[currVertex]            = startVertex;
                        ds.Vertices[currVertex].label = $"{Math.Round(dist[currEdge.end], 3)}+{Math.Round(edge.w, 3)}";
                        ds.Invalidate();
                        Thread.Sleep(1000);
                        que.Add(edge);
                    }
                    ds.Vertices[currVertex].label = (dist[currVertex] == int.MaxValue) ? "INF" : $"{dist[currVertex]}";
                    ReDrawEdge(ds, edge, Color.Gray, 0);
                }
            }
            msg.SetTitle("Dijkstra algorithm result:");
            msg.MoveToCorner(ds.FindForm() as Form1);
            msg.StartMenu();
            for (var target = 0; target < adjList.Count; ++target)
            {
                if (start != target)
                {
                    var currWay = GetWay(start, target, parent);
                    PrintWay(currWay, dist[target]);
                    Thread.Sleep(1000);
                }
            }
            msg.WaitOne();
            ClearEdges(ds);
            ClearVertices(ds);
        }