public void GraphWithOptions()
{
var g = new TestGraph(Enumerable.Range(1, 6).ToArray())
{
{ 1, new[] { 2 } },
{ 2, new[] { 4 } },
{ 3, new[] { 4, 6 } },
{ 4 },
{ 5, new[] { 6 } },
{ 6 },
};
g.AddEdge(2, 3, 1);
g.AddEdge(3, 5, 1);
var spGraph = ShortestPathGraphWithOptions.Build(g, edge => edge.IsFree || edge.MustUseOption, new[] { 1 }, 1);
var testShortestPathGraph = new TestShortestPathGraph
{
{ 1, 0, new[] { 2 } },
{ 2, 1, new[] { 4, 3 } },
{ 3, 2, new[] { 5, 6 } },
{ 4, 2, null, new[] { 3 } },
{ 5, 4 },
{ 6, 3, new[] { 5 } },
};
testShortestPathGraph[2].Edges.Single(e => e.To == 3).River.Owner = 1;
testShortestPathGraph[3].Edges.Single(e => e.To == 5).River.Owner = 1;
spGraph.ShouldBeEquivalentTo(testShortestPathGraph);
}
public static ShortestPathGraphWithOptions Build(Graph graph, Func <Edge, bool> takeEdge, ICollection <int> sourceVertexes, int optionsCount)
{
var queue = new SortedSet <QueueItem>();
var dist = CreateMap(new { OptionsUsed = 0, VertexId = 0 }, 0);
foreach (var sourceVertex in sourceVertexes)
{
queue.Add(new QueueItem(0, 0, sourceVertex));
dist[new { OptionsUsed = 0, VertexId = sourceVertex }] = 0;
}
while (queue.Any())
{
var item = queue.Min();
queue.Remove(item);
var from = item.VertexId;
if (dist[new { item.OptionsUsed, item.VertexId }] != item.Distance)
{
continue;
}
foreach (var edge in graph.Vertexes[from].Edges)
{
if (!takeEdge(edge))
{
continue;
}
var to = edge.To;
var nextOptions = item.OptionsUsed + (edge.MustUseOption ? 1 : 0);
if (nextOptions > optionsCount)
{
continue;
}
var newDistance = item.Distance + 1;
if (dist.TryGetValue(new { OptionsUsed = nextOptions, VertexId = to }, out var curDistance) && curDistance <= newDistance)
{
continue;
}
dist[new { OptionsUsed = nextOptions, VertexId = to }] = newDistance;
queue.Add(new QueueItem(nextOptions, newDistance, to));
}
}
var spGraph = new ShortestPathGraphWithOptions();
var vertexDistances = dist.GroupBy(x => x.Key.VertexId)
.ToDictionary(distances => distances.Key, distances => distances.Min(d => d.Value));
foreach (var item in vertexDistances)
{
spGraph.AddVertex(item.Key, item.Value);
}
foreach (var from in spGraph.Vertexes.Values)
{
foreach (var edge in graph.Vertexes[from.Id].Edges)
{
var to = spGraph[edge.To];
if (to.Distance == -1)
{
continue;
}
if (to.Distance == from.Distance && from.Id < to.Id)
{
spGraph.AddSameLayerEdge(edge);
}
if (to.Distance > from.Distance)
{
spGraph.AddEdge(edge);
}
}
}
return(spGraph);
}