public void TestHasAnotherMatching()
{
var graph = new BipartiteGraph(2, 2);
graph.AddEdge(0, 0);
graph.AddEdge(0, 1);
graph.AddEdge(1, 1);
var matching = new Matching(2);
matching.AddPair(0, 0);
matching.AddPair(1, 1);
Assert.IsFalse(builder.HasAnotherMatching(graph, matching));
}
public bool HasAnotherMatching(BipartiteGraph graph, Matching matching)
{
for (var i = 0; i < graph.SecondPartSize; i++)
{
if (matching.HasPair(i))
{
var pair = matching.GetPair(i);
matching.RemovePair(i);
graph.RemoveEdge(pair, i);
var used = new bool[graph.FirstPartSize];
if (TryKuhn(pair, used, graph, matching))
{
matching.AddPair(i, pair);
graph.AddEdge(pair, i);
return(true);
}
matching.AddPair(i, pair);
graph.AddEdge(pair, i);
}
}
return(false);
}
private bool TryKuhn(int v, bool[] used, BipartiteGraph bipartiteGraph, Matching matching)
{
if (used[v])
{
return(false);
}
used[v] = true;
for (var i = 0; i < bipartiteGraph.SecondPartSize; ++i)
{
if (bipartiteGraph.IsConnected(v, i))
{
var to = i;
if (!matching.HasPair(to) || TryKuhn(matching.GetPair(to), used, bipartiteGraph, matching))
{
matching.AddPair(to, v);
return(true);
}
}
}
return(false);
}
