pNode RB_Delete(pNode root,pNode t)
{
pNode DelNode;
//{* get tthe node to delete
if((t -> left == Nil) || (t -> right == Nil) )
DelNode = t;
else
DelNode = Tree_Successor(t);
//*}
pNode PreserveNode;
if( DelNode -> left != Nil)
PreserveNode = DelNode -> left;
else
PreserveNode = DelNode -> right;
PreserveNode -> parent = DelNode -> parent; // link the DelNode's parent to PreserveNode
if( DelNode == Nil ) //if DelNode is the root
root = PreserveNode;
else {
if(DelNode == (DelNode -> parent -> left))
DelNode -> parent -> left = PreserveNode;
else
DelNode -> parent -> right = PreserveNode;
}
if(DelNode != t)
t -> key = DelNode -> key;
/*
* if the DelNode's color is black, we must fixup RBT to keep the properties of RBT.
* */
if(DelNode -> color == "BLACK")
root = RB_Delete_Fixup(root, PreserveNode);
return PreserveNode;
}
redblack_node *
redblack_node::RB_Delete(
redblack_node *T,
redblack_node* z
)
{
redblack_node *y, *x, *temp = T;
while( temp->parent != NULL )
temp = temp->parent; // point temp to the root of T
if( z == NULL )
z = new redblack_node;
if( z->left == NULL || z->right == NULL )
y = z;
else
y = static_cast<redblack_node *>(Tree_Successor( z ));
if( y == NULL )
y = new redblack_node();
if( y->left != NULL )
x = y->left;
else
x = y->right;
if( x == NULL )
x = new redblack_node;
x->parent = y->parent;
if( y->parent == NULL )
temp = x;
else if( y == y->parent->left )
y->parent->left = x;
else
y->parent->right = x;
if( y != z )
z->data = strdup( y->data );
if( strcmp( y->color, "BLACK" ) == 0 )
RB_Delete_Fixup( T, x );
return y;
}
