public void DisjointSetForestUnionTest()
{
DisjointSetForest <Int32> disjointSetInt = new DisjointSetForest <Int32>();
DisjointSetForest <String> disjointSetString = new DisjointSetForest <String>();
foreach (Int32 value in _values)
{
disjointSetInt.MakeSet(value);
disjointSetString.MakeSet(value.ToString());
}
for (Int32 i = 0; i < _values.Length; i = i + 2)
{
disjointSetInt.Union(_values[i], _values[i + 1]);
disjointSetString.Union(_values[i].ToString(), _values[i + 1].ToString());
}
// testing representatives
for (Int32 i = 0; i < _values.Length; i = i + 2)
{
Assert.AreEqual(disjointSetInt.Find(_values[i]), disjointSetInt.Find(_values[i + 1]));
Assert.AreEqual(disjointSetString.Find(_values[i].ToString()), disjointSetString.Find(_values[i + 1].ToString()));
}
// testing setCounts
Assert.AreEqual(disjointSetInt.SetCount, _values.Length / 2);
Assert.AreEqual(disjointSetString.SetCount, _values.Length / 2);
Assert.AreEqual(disjointSetInt.Count, _values.Length);
Assert.AreEqual(disjointSetString.Count, _values.Length);
// exceptions
Assert.Throws <ArgumentException>(() => disjointSetInt.Union(_values[0], 100));
Assert.Throws <ArgumentException>(() => disjointSetInt.Union(100, _values[0]));
Assert.Throws <ArgumentException>(() => disjointSetInt.Union(100, 101));
Assert.Throws <ArgumentException>(() => disjointSetString.Union(_values[0].ToString(), 100.ToString()));
Assert.Throws <ArgumentException>(() => disjointSetString.Union(100.ToString(), _values[0].ToString()));
Assert.Throws <ArgumentException>(() => disjointSetString.Union(100.ToString(), 101.ToString()));
Assert.Throws <ArgumentNullException>(() => disjointSetString.Union(_values[0].ToString(), null));
Assert.Throws <ArgumentNullException>(() => disjointSetString.Union(null, _values[0].ToString()));
Assert.Throws <ArgumentNullException>(() => disjointSetString.Union(null, null));
}
/// <summary>
/// Computes the result of the operation.
/// </summary>
protected override void ComputeResult()
{
_forest = new DisjointSetForest <IGraphVertex>(Source.Vertices);
foreach (IGraphEdge edge in Source.Edges.OrderBy(x => _weightMetric(x)))
{
if (_forest.Find(edge.Source) != _forest.Find(edge.Target))
{
_spanningEdges.Add(edge);
_forest.Union(edge.Source, edge.Target);
}
}
}
/// <summary>
/// Computes the result of the operation.
/// </summary>
protected override void ComputeResult()
{
_edgeSet = new HashSet <IGraphEdge>();
_forest = new DisjointSetForest <IGraphVertex>(Source.Vertices);
while (_forest.SetCount > 1)
{
IGraphVertex currentRep = null;
foreach (IGraphVertex vertex in _forest.OrderedEnumerator)
{
if (currentRep != _forest.Find(vertex))
{
//new component
currentRep = _forest.Find(vertex);
if (_edgeSet.Count > 0)
{
_spanningEdges.Add(_edgeSet.MinBy(x => _weightMetric(x)).First());
}
_edgeSet.Clear();
}
if (Source.OutEdges(vertex).Any(x => _forest.Find(x.Target) != currentRep))
{
_edgeSet.Add(
Source.OutEdges(vertex)
.Where(x => _forest.Find(x.Target) != currentRep)
.MinBy(y => _weightMetric(y))
.First());
}
}
if (_edgeSet.Count > 0)
{
//on the last element there is no component change
_spanningEdges.Add(_edgeSet.MinBy(x => _weightMetric(x)).First());
}
_edgeSet.Clear();
foreach (IGraphEdge spanningEdge in _spanningEdges)
{
_forest.Union(spanningEdge.Source, spanningEdge.Target);
}
}
}