/// <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);
}
