private void Build(KV <T, K>[] KeysAndValues, int Low, int High, HyperRect <T> Region, int Depth)
{
int Dimension = Depth % KeysAndValues[Low].Dimensions;
int N = Ninther(KeysAndValues, Low, High, Dimension);
_Value = KeysAndValues[N];
_Region = Region;
Swap(KeysAndValues, N, High);
int j = Low;
for (int i = Low; i < High; ++i)
{
if (KeysAndValues[i].CompareTo(KeysAndValues[High], Dimension) < 0)
{
Swap(KeysAndValues, i, j++);
}
}
Pair <HyperRect <T>, HyperRect <T> > Subregions = _Region.Split(_Value.First, Dimension);
if (Low <= j - 1)
{
_Left = new KDTree <T, K>(KeysAndValues, Low, j - 1, Subregions.First, Depth + 1);
}
if (j <= High - 1)
{
_Right = new KDTree <T, K>(KeysAndValues, j, High - 1, Subregions.Second, Depth + 1);
}
}
public bool Contains(HyperRect <T> Rect)
{
for (int i = 0; i < _Left.Dimensions; ++i)
{
if (Rect._Left.CompareTo(_Left, i) < 0 || Rect._Right.CompareTo(_Right, i) > 0)
{
return(false);
}
}
return(true);
}
public HyperRect <T> Join(HyperRect <T> Second)
{
T L = Left;
T R = Second.Right;
for (int i = 0; i < L.Dimensions; ++i)
{
L.SetDimension(i,
Left.CompareTo(Second.Left, i) < 0 ? Left.GetDimension(i) : Second.Left.GetDimension(i));
R.SetDimension(i,
Right.CompareTo(Second.Left, i) > 0 ? Right.GetDimension(i) : Second.Right.GetDimension(i));
}
return(new HyperRect <T>(L, R));
}
public KDTree(KV <T, K>[] KeysAndValues, int Low, int High, HyperRect <T> Region, int Depth)
{
Build(KeysAndValues, Low, High, Region, Depth);
}
public KDTree(IEnumerable <KV <T, K> > KeysAndValues)
{
KV <T, K>[] V = KeysAndValues.ToArray();
Shuffle(V);
Build(V, 0, V.Length - 1, HyperRect <T> .Bound(V.Select(i => i.First)), 0);
}