Diese Auflistungsklasse verwaltet Duplikate und fügt die Sortierreihenfolge für das Duplikat ein. Der Trick besteht darin, die Elemente beim Einfügen mit einem eindeutigen Wert zu versehen, um eine stabile Sortierreihenfolge aufrechtzuerhalten. Dann packen wir alles in eine ICollection-Oberfläche.
public class SuperSortedSet<TValue> : ICollection<TValue>
{
private readonly SortedSet<Indexed<TValue>> _Container;
private int _Index = 0;
private IComparer<TValue> _Comparer;
public SuperSortedSet(IComparer<TValue> comparer)
{
_Comparer = comparer;
var c2 = new System.Linq.Comparer<Indexed<TValue>>((p0, p1) =>
{
var r = _Comparer.Compare(p0.Value, p1.Value);
if (r == 0)
{
if (p0.Index == -1
|| p1.Index == -1)
return 0;
return p0.Index.CompareTo(p1.Index);
}
else return r;
});
_Container = new SortedSet<Indexed<TValue>>(c2);
}
public IEnumerator<TValue> GetEnumerator() { return _Container.Select(p => p.Value).GetEnumerator(); }
IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); }
public void Add(TValue item) { _Container.Add(Indexed.Create(_Index++, item)); }
public void Clear() { _Container.Clear();}
public bool Contains(TValue item) { return _Container.Contains(Indexed.Create(-1,item)); }
public void CopyTo(TValue[] array, int arrayIndex)
{
foreach (var value in this)
{
if (arrayIndex >= array.Length)
{
throw new ArgumentException("Not enough space in array");
}
array[arrayIndex] = value;
arrayIndex++;
}
}
public bool Remove(TValue item) { return _Container.Remove(Indexed.Create(-1, item)); }
public int Count {
get { return _Container.Count; }
}
public bool IsReadOnly {
get { return false; }
}
}
eine Testklasse
[Fact]
public void ShouldWorkWithSuperSortedSet()
{
// Sort points according to X
var set = new SuperSortedSet<Point2D>
(new System.Linq.Comparer<Point2D>((p0, p1) => p0.X.CompareTo(p1.X)));
set.Add(new Point2D(9,10));
set.Add(new Point2D(1,25));
set.Add(new Point2D(11,-10));
set.Add(new Point2D(2,99));
set.Add(new Point2D(5,55));
set.Add(new Point2D(5,23));
set.Add(new Point2D(11,11));
set.Add(new Point2D(21,12));
set.Add(new Point2D(-1,76));
set.Add(new Point2D(16,21));
var xs = set.Select(p=>p.X).ToList();
xs.Should().BeInAscendingOrder();
xs.Count.Should()
.Be(10);
xs.ShouldBeEquivalentTo(new[]{-1,1,2,5,5,9,11,11,16,21});
set.Remove(new Point2D(5,55));
xs = set.Select(p=>p.X).ToList();
xs.Count.Should()
.Be(9);
xs.ShouldBeEquivalentTo(new[]{-1,1,2,5,9,11,11,16,21});
set.Remove(new Point2D(5,23));
xs = set.Select(p=>p.X).ToList();
xs.Count.Should()
.Be(8);
xs.ShouldBeEquivalentTo(new[]{-1,1,2,9,11,11,16,21});
set.Contains(new Point2D(11, 11))
.Should()
.BeTrue();
set.Contains(new Point2D(-1, 76))
.Should().BeTrue();
// Note that the custom compartor function ignores the Y value
set.Contains(new Point2D(-1, 66))
.Should().BeTrue();
set.Contains(new Point2D(27, 66))
.Should().BeFalse();
}
Die Tagging-Struktur
public struct Indexed<T>
{
public int Index { get; private set; }
public T Value { get; private set; }
public Indexed(int index, T value) : this()
{
Index = index;
Value = value;
}
public override string ToString()
{
return "(Indexed: " + Index + ", " + Value.ToString () + " )";
}
}
public class Indexed
{
public static Indexed<T> Create<T>(int indexed, T value)
{
return new Indexed<T>(indexed, value);
}
}
Der Lambda-Vergleichshelfer
public class Comparer<T> : IComparer<T>
{
private readonly Func<T, T, int> _comparer;
public Comparer(Func<T, T, int> comparer)
{
if (comparer == null)
throw new ArgumentNullException("comparer");
_comparer = comparer;
}
public int Compare(T x, T y)
{
return _comparer(x, y);
}
}