public void TestBinaryMinHeap(BinaryMinHeap <char> sut)
{
var expected = new[] { 'a', 'b', 'd', 'e', 'c', 'f', 'g' };
var actual = expected.Select(_ => sut.ExtractMinimum());
Assert.True(expected.SequenceEqual(actual.Select(_ => _.Id)));
}
private IEnumerable <Edge> GetMinimumSpanningTreeEdgesBad(Dictionary <char, List <Edge> > g)
{
var h = new BinaryMinHeap <char>();
var vte = new Dictionary <char, Edge>();
// Fill Heap
var isFirst = true;
foreach (char key in g.Keys)
{
if (isFirst)
{
h.Add(new BinaryMinHeap <char> .Node {
Id = key, Weight = 0
});
isFirst = false;
}
else
{
h.Add(new BinaryMinHeap <char> .Node {
Id = key, Weight = int.MaxValue
});
}
}
var result = new List <Edge>();
while (h.HasItem())
{
var v = h.ExtractMinimum();
vte.TryGetValue(v.Id, out Edge ste);
if (ste != null)
{
result.Add(ste);
}
foreach (Edge e in g[v.Id])
{
char adj = e.V2;
if (!h.Contains(adj))
{
continue;
}
var node = h.GetNode(adj);
if (node.Weight > e.Weight)
{
node.Weight = e.Weight;
h.Decrease(node);
if (!vte.ContainsKey(node.Id))
{
vte.Add(node.Id, e);
}
vte[node.Id] = e;
}
}
}
return(result);
}
public void TestBinaryMinHeapDecrease()
{
var sut = new BinaryMinHeap <char>();
var a = new BinaryMinHeap <char> .Node {
Id = 'a', Weight = -1
};
var b = new BinaryMinHeap <char> .Node {
Id = 'b', Weight = 2
};
var c = new BinaryMinHeap <char> .Node {
Id = 'c', Weight = 6
};
var d = new BinaryMinHeap <char> .Node {
Id = 'd', Weight = 4
};
var e = new BinaryMinHeap <char> .Node {
Id = 'e', Weight = 5
};
var f = new BinaryMinHeap <char> .Node {
Id = 'f', Weight = 7
};
var g = new BinaryMinHeap <char> .Node {
Id = 'g', Weight = 8
};
sut.Add(a);
sut.Add(b);
sut.Add(c);
sut.Add(d);
sut.Add(e);
sut.Add(f);
sut.Add(g);
f.Weight = -2;
sut.Decrease(f);
g.Weight = -3;
sut.Decrease(g);
var expected = new[] { 'g', 'f', 'a', 'b', 'd', 'e', 'c' };
var actual = expected.Select(_ => sut.ExtractMinimum());
//foreach (BinaryMinHeap<char>.Node node in actual)
//{
// _output.WriteLine(node.ToString());
//}
Assert.True(expected.SequenceEqual(actual.Select(_ => _.Id)));
}
public void ThrowExceptionWhenExtractingAnEmptyBinaryMinHeap()
{
var sut = new BinaryMinHeap <char>();
Assert.Throws <ArgumentOutOfRangeException>(() => sut.ExtractMinimum());
}
