/// <summary>
/// Indica si el par {llave,valor} está contenida en el B-Tree
/// </summary>
/// <param name="key">Llave a verificar</param>
/// <returns></returns>
public bool Contains(T key, R value)
{
MiPar <T, R> result = Search(key, value);
if (result == null)
{
return(false);
}
return(true);
}
/// <summary>
/// Elimina del B-Tree el par {llave,valor} a partir de la raíz
/// </summary>
/// <param name="x">Nodo raíz</param>
/// <param name="k">Llave a eliminar</param>
/// <param name="v">Valor a eliminar</param>
/// <returns></returns>
private MiPar <T, R> Delete(BTreeNode <T, R> x, T k, R v)
{
int index = buscarEnNodo(x, k, v, false);
//int index = buscarEnNodoSec(x, k, v);
if (x.IsLeaf)//Caso 1
{
if (index == -1)
{
return(null);
}
MiPar <T, R> result = new MiPar <T, R>(x.Keys[index], x.Satellite[index]);
for (int i = index; i < x.CantKeys - 1; i++)
{
x.Keys[i] = x.Keys[i + 1];
x.Satellite[i] = x.Satellite[i + 1];
}
x.CantKeys--;
//RAM.Update(x);
return(result);
}
else //x es un nodo interno(casos 2 y 3)
{
if (index != -1)//x contiene a k(caso 2)
{
BTreeNode <T, R> y = GetNode(x.Children[index]); //llamar al FileManager y DISK_READ(x.Children[index]) predecessor child;
if (y.CantKeys >= t) //y tiene al menos t llaves
{ //caso 2a
BTreeNode <T, R> max = Maximo(y);
T aux = max.Keys[max.CantKeys - 1];
R val = max.Satellite[max.CantKeys - 1]; //addded
x.Keys[index] = aux;
x.Satellite[index] = val; //added
//RAM.Update(x);//added
return(Delete(y, aux, val));
}
else //y tiene t-1 llaves
{ //caso 2b
BTreeNode <T, R> z = GetNode(x.Children[index + 1]);//llamar al FileManager y DISK_READ(x.Children[index + 1]) sucessor child;
if (z.CantKeys >= t)
{
BTreeNode <T, R> min = Minimo(z);
T aux = min.Keys[0];
R val = min.Satellite[0]; //added
x.Keys[index] = aux;
x.Satellite[index] = val; //added
//RAM.Update(z);//added
return(Delete(z, aux, val));
}
else//tanto y como z tienen t-1 llaves
{//caso 2c
Merge(x, y, z, index);//revisar bien aqui(buscar en la hoja del pseudocodigo)
return(Delete(y, k, v));
}
}
}
else//x no contiene a k(caso 3)
{
int i = 0;
while (i < x.CantKeys && Compare(k, x.Keys[i], v, x.Satellite[i]) > 0)//change k.CompareTo(x.Keys[i]) > 0
{
i++;
}
BTreeNode <T, R> c = GetNode(x.Children[i]);//DISK_READ(x.Children[i]);
if (c.CantKeys == t - 1)
{
bool primero = (i == 0);
bool ultimo = (i == x.CantKeys);
BTreeNode <T, R> y = new BTreeNode <T, R>();
BTreeNode <T, R> z = new BTreeNode <T, R>();
if (!primero)
{
y = GetNode(x.Children[i - 1]);// DISK_READ(x.Children[i-1]) predecessor brother;
}
if (!ultimo)
{
z = GetNode(x.Children[i + 1]); //DISK_READ(x.Children[i+1]) sucessor brother;
}
if ((!primero && y.CantKeys >= t) || (!ultimo && z.CantKeys >= t)) //caso 3a
{
if (!primero && y.CantKeys >= t)
{
//la llave a bajar del padre es la i-1
Array.Copy(c.Keys, 0, c.Keys, 1, c.CantKeys);
Array.Copy(c.Satellite, 0, c.Satellite, 1, c.CantKeys);//added
Array.Copy(c.Children, 0, c.Children, 1, c.CantKeys + 1);
c.Keys[0] = x.Keys[i - 1];
c.Satellite[0] = x.Satellite[i - 1];//added
c.Children[0] = y.Children[y.CantKeys];
x.Keys[i - 1] = y.Keys[y.CantKeys - 1];
x.Satellite[i - 1] = y.Satellite[y.CantKeys - 1];//added
c.CantKeys++;
y.CantKeys--;
//RAM.Update(x);
//RAM.Update(c);
//RAM.Update(y);
}
else if (!ultimo && z.CantKeys >= t)
{
//la llave a bajar del padre es la i
c.Keys[c.CantKeys] = x.Keys[i];
c.Satellite[c.CantKeys] = x.Satellite[i];//added
c.Children[c.CantKeys + 1] = z.Children[0];
x.Keys[i] = z.Keys[0];
x.Satellite[i] = z.Satellite[0]; //added
Array.Copy(z.Keys, 1, z.Keys, 0, z.CantKeys - 1);
Array.Copy(z.Satellite, 1, z.Satellite, 0, z.CantKeys - 1); //added
Array.Copy(z.Children, 1, z.Children, 0, z.CantKeys);
c.CantKeys++;
z.CantKeys--;
//RAM.Update(x);
//RAM.Update(c);
//RAM.Update(z);
}
return(Delete(c, k, v));
}
else //c y sus dos hermanos tienen t-1 llaves
{
//caso 3b
if (!primero)
{
Merge(x, y, c, i - 1);
return(Delete(y, k, v));
}
else /*if (!ultimo)*/
{
Merge(x, c, z, i /*i-1*/);
return(Delete(c, k, v));
}
}
// if (!primero && y.CantKeys >= t)
// return Delete(y, k, v);
// else
// return Delete(c, k, v);
}
else
{
return(Delete(c, k, v));
}
}
}
}