private void InitializePreflow(AdjacencyListGraph <T> graph
, AdjacencyVertex <T> source)
{
var vertexs = graph.GetVertexs();
foreach (var vertex in vertexs)
{
vertex.Height = 0;
vertex.Preflow = 0;
}
var edges = graph.GetEdges();
foreach (FlowEdge <T> edge in edges)
{
edge.Flow = 0;
edge.Revolution.Flow = 0;
}
source.Height = vertexs.Count();
var sourceEdges = graph.GetVertexEdge(source);
foreach (FlowEdge <T> sourceEdge in sourceEdges)
{
sourceEdge.Flow = sourceEdge.Capacity;
sourceEdge.Revolution.Flow = -sourceEdge.Capacity;
sourceEdge.End.Preflow = sourceEdge.Capacity;
source.Preflow = source.Preflow - sourceEdge.Capacity;
}
}
/// <summary>
/// 单源最短路径会把一个点到其它所有点的最短路径算出来
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="graph"></param>
/// <param name="source"></param>
/// <param name="weightFuc"></param>
/// <returns></returns>
public static void Dijkstra <T>(
this AdjacencyListGraph <T> graph,
AdjacencyVertex <T> source,
Func <AdjacencyListGraph <T>, AdjacencyVertex <T>, AdjacencyVertex <T>, int> weightFuc
) where T : IEquatable <T>
{
graph.InitializeSingleSource(source);
var calcVertexs = new List <AdjacencyVertex <T> >();
var vertexs = graph.GetVertexs().ToList();
//不想再增加AdjacencyVertex对象的负担了
var queue = new ExtentionBinanyHeap <AdjacencyVertex <T> >
(
vertexs,
(first, second) =>
{
return(first.WeightBound < second.WeightBound);
}
);
// while (!queue.IsEmpty) 竟然把while写成if有才
while (!queue.IsEmpty)
{
var min = queue.Extract();
Console.WriteLine("calcVertex");
Console.WriteLine(min);
calcVertexs.Add(min);
var edges = graph.GetVertexEdge(min);
foreach (var edge in edges)
{
var oldWeight = edge.End.WeightBound;
Relax(graph, edge.Start, edge.End, weightFuc);
//没有索引位置一下让我傻逼了!网上找了一下也是有调整的。
if (oldWeight != edge.End.WeightBound)
{
queue.UpdateKey(edge.End, edge.End);
}
}
}
}
/// <summary>
/// 怎么输出最小生成树？
/// 很神奇的是这个贪心算法是对的
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="graph"></param>
/// <param name="root"></param>
/// <param name="weightFunc"></param>
public static IList <AdjacencyEdge <T> > GetMininumSpanningTreePrim <T>(
this AdjacencyListGraph <T> graph,
AdjacencyVertex <T> root,
Func <AdjacencyEdge <T>, int> weightFunc
) where T : IEquatable <T>
{
var vertexs = graph.GetVertexs().ToList();
//TempStorage顶点到到某一顶点相连的最小权值。
foreach (var vertex in vertexs)
{
vertex.TempStorage = int.MaxValue;
vertex.Predecessor = null;
}
root.TempStorage = 0;
var result = new List <AdjacencyEdge <T> >();
var queue = new ExtentionBinanyHeap <AdjacencyVertex <T> >(vertexs, (f, s) => f.TempStorage < s.TempStorage);
while (!queue.IsEmpty)
{
var min = queue.Extract();
if (min != root)
{
result.Add(graph.GetEdge(min.Predecessor, min));
}
var edges = graph.GetVertexEdge(min);
foreach (var edge in edges)
{
var weight = weightFunc(edge);
//TODO: 还有一个包含判断
if (edge.End.BelongedHeap == queue && weight < edge.End.TempStorage)
{
edge.End.Predecessor = min;
edge.End.TempStorage = weight;
queue.UpdateKey(edge.End, edge.End);
}
}
}
return(result);
}
public IDictionary <AdjacencyVertex <T>, FlowEdge <T> > GetResidualPath(
AdjacencyListGraph <T> graph
, AdjacencyVertex <T> source
, AdjacencyVertex <T> target)
{
var path = new Dictionary <AdjacencyVertex <T>, FlowEdge <T> >();
var vertexs = graph.GetVertexs();
foreach (var vertex in vertexs)
{
vertex.Predecessor = null;
}
path[source] = null;
var queue = new Queue <AdjacencyVertex <T> >();
queue.Enqueue(source);
while (!queue.IsEmpty)
{
var current = queue.Dequeue();
var currentEdges = graph.GetVertexEdge(current);
foreach (FlowEdge <T> currentEdge in currentEdges)
{
if (currentEdge.End != source &&
currentEdge.End.Predecessor == null &&
currentEdge.Capacity > currentEdge.Flow
)
{
path[currentEdge.End] = currentEdge;
currentEdge.End.Predecessor = current;
queue.Enqueue(currentEdge.End);
}
}
}
if (target.Predecessor == null)
{
return(null);
}
return(path);
}
/// <summary>
/// 有向无回路图
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="graph"></param>
/// <param name="source"></param>
/// <param name="weightFuc"></param>
/// <returns></returns>
public static void DAGShortestPath <T>(
this AdjacencyListGraph <T> graph,
AdjacencyVertex <T> source,
Func <AdjacencyListGraph <T>, AdjacencyVertex <T>, AdjacencyVertex <T>, int> weightFuc
) where T : IEquatable <T>
{
graph.TopologicalSort();
graph.InitializeSingleSource(source);
var vertexs = graph.GetVertexs();
foreach (var orderVertex in vertexs)
{
var edges = graph.GetVertexEdge(orderVertex);
foreach (var edge in edges)
{
graph.Relax(edge.Start, edge.End, weightFuc);
}
}
}