private void AssertEdges(IMinimalSpanTreeSearch algorithm, IGraphDefinition graph, params int[] edgeIds)
{
var edges = algorithm.GetMST(graph).ToList();
Assert.AreEqual(edgeIds.Length, edges.Count);
foreach (var edgeId in edgeIds)
{
Assert.IsTrue(edges.Any(x => x.Id == edgeId), $"Edge: {edgeId} not found in : {string.Join(",", edges.Select(x => x.Id))}");
}
}
/// <inheritdoc/>
public IEnumerable <Edge> GetMST(IGraphDefinition graphDefinition)
{
if (graphDefinition == null)
{
throw new ArgumentNullException(nameof(graphDefinition));
}
var allVertexes = graphDefinition.Vertices.ToList();
if (allVertexes.Count <= 1)
{
throw new ArgumentException("Minimal vertexes count is 2", nameof(graphDefinition));
}
var firstVertex = allVertexes[0];
var notDistributedVertexes = new List <VertextExt>();
for (var i = 1; i < allVertexes.Count; ++i)
{
var edges = graphDefinition.GetEdges(firstVertex, allVertexes[i]).ToList();
notDistributedVertexes.Add(new VertextExt {
Vertex = allVertexes[i], Winner = edges.Any() ? edges.OrderBy(x => x.Weight).Min() : null
});
}
var heap = new VertextHeap(notDistributedVertexes);
while (!heap.IsEmpty)
{
var heapElement = heap.Extract();
var closestVertex = heapElement.Value;
if (closestVertex.Winner == null)
{
throw new InvalidOperationException("Graph is not connected");
}
for (var i = 0; i < heap.Count; ++i)
{
var vertex = heap.Heap[i].Value.Vertex;
if (graphDefinition.EdgeExists(closestVertex.Vertex, vertex))
{
var closestEdge = graphDefinition.GetEdges(closestVertex.Vertex, vertex).OrderBy(x => x.Weight).First();
if (heap.Heap[i].Value.Winner == null || heap.Heap[i].Key > closestEdge.Weight)
{
heap.EditElementKey(vertex, closestEdge);
}
}
}
yield return(closestVertex.Winner);
}
}
/// <inheritdoc/>
public IEnumerable <Edge> GetMST(IGraphDefinition graphDefinition)
{
var edges = graphDefinition.Edges.ToArray();
var vertexes = graphDefinition.Vertices.Select(x => new VertexUnionFindItem {
Id = x.Id, Vertex = x
}).ToList();
var vertexesDict = vertexes.ToDictionary(x => x.Id, x => x);
_sortAlgorithm.Sort(edges);
var unionFind = new UnionFind <int>(vertexes);
foreach (var edge in edges)
{
var(from, to) = graphDefinition.GetVertexPair(edge);
var firstParent = unionFind.Find(vertexesDict[from.Id]);
var secondParent = unionFind.Find(vertexesDict[to.Id]);
if (firstParent != secondParent)
{
unionFind.Union(vertexesDict[from.Id], vertexesDict[to.Id]);
yield return(edge);
}
}
}
