static
HRESULT RBDelete(std_map* self, std_map_node* z)
{
std_map_node* y;
std_map_node* x;
std_map_node* nil=self->m_pNil;
std_map_node* root=self->m_pRoot;
y= ((z->pLeft == nil) || (z->pRight == nil)) ? z : TreeSuccessor(self,z);
x= (y->pLeft == nil) ? y->pRight : y->pLeft;
if (root == (x->pParent = y->pParent))
{ /* assignment of y->p to x->p is intentional */
root->pLeft=x;
}
else
{
if (y == y->pParent->pLeft)
{
y->pParent->pLeft=x;
} else {
y->pParent->pRight=x;
}
}
if (y != z)
{ /* y should not be nil in this case */
/* y is the node to splice out and x is its child */
if (!(y->bRed)) RBDeleteFixUp(self,x);
KeyDtor(self, z->pKey);
DataDtor(self, z->pData);
y->pLeft=z->pLeft;
y->pRight=z->pRight;
y->pParent=z->pParent;
y->bRed=z->bRed;
z->pLeft->pParent=z->pRight->pParent=y;
if (z == z->pParent->pLeft)
{
z->pParent->pLeft=y;
}
else
{
z->pParent->pRight=y;
}
GaloisFree(z);
}
else
{
KeyDtor(self, y->pKey);
DataDtor(self, y->pData);
if (!(y->bRed)) RBDeleteFixUp(self,x);
GaloisFree(y);
}
return S_OK;
}
void rb_tree_delete(rb_red_blk_tree* tree, rb_red_blk_node* z){
rb_red_blk_node* y;
rb_red_blk_node* x;
rb_red_blk_node* nil=tree->nil;
rb_red_blk_node* root=tree->root;
y= ((z->left == nil) || (z->right == nil)) ? z : rb_tree_successor(tree,z);
x= (y->left == nil) ? y->right : y->left;
if (root == (x->parent = y->parent)) { /* assignment of y->p to x->p is intentional */
root->left=x;
} else {
if (y == y->parent->left) {
y->parent->left=x;
} else {
y->parent->right=x;
}
}
if (y != z) { /* y should not be nil in this case */
#ifdef DEBUG_ASSERT
Assert( (y!=tree->nil),"y is nil in RBDelete\n");
#endif
/* y is the node to splice out and x is its child */
if (!(y->red)) RBDeleteFixUp(tree,x);
tree->key_dtor_func(z->key);
tree->info_dtor_func(z->info);
y->left=z->left;
y->right=z->right;
y->parent=z->parent;
y->red=z->red;
z->left->parent=z->right->parent=y;
if (z == z->parent->left) {
z->parent->left=y;
} else {
z->parent->right=y;
}
free(z);
} else {
tree->key_dtor_func(y->key);
tree->info_dtor_func(y->info);
if (!(y->red)) RBDeleteFixUp(tree,x);
free(y);
}
#ifdef DEBUG_ASSERT
Assert(!tree->nil->red,"nil not black in RBDelete");
#endif
}
void RBTree::RBDelete(int key) {
rb_red_blk_node* y;
rb_red_blk_node* x;
rb_red_blk_node* nil=tree->nil;
rb_red_blk_node* root=tree->root;
rb_red_blk_node* z = RBExactQuery(key);
if (!z) {
return;
}
y= ((z->left == nil) || (z->right == nil)) ? z : TreeSuccessor(z);
/* XXX: original code was : x= (y->left == nil) ? y->right : y->left; */
x= (y->left > nil) ? y->right : y->left;
if (root == (x->parent = y->parent)) { root->left=x;
} else {
if (y == y->parent->left) {
y->parent->left=x;
} else {
y->parent->right=x;
}
}
if (y != z) {
if (!(y->red)) RBDeleteFixUp(x);
y->left=z->left;
y->right=z->right;
y->parent=z->parent;
y->red=z->red;
z->left->parent=z->right->parent=y;
if (z == z->parent->left) {
z->parent->left=y;
} else {
z->parent->right=y;
}
free(z);
} else {
if (!(y->red)) RBDeleteFixUp(x);
free(y);
}
}
/*
* This function is used to delete a node z from the tree
* specified by root
*
* @param Root reference to the main tree
* @param z node to delete to the main tree
* @return N/A
*/
void RBDelete(RBTNode **Root, RBTNode *z)
{
RBTNode *yNode;
RBTNode *xNode;
RBTNode *parentNode;
BOOL leftNode = false;
//if the node has less than two children, we can use it.
//otherwise we have to find the successor
if (z->leftChild == NULL || z->rightChild == NULL)
{
yNode = z;
}
else
{
yNode = Successor(z);
}
//if y has a left child, use it
//otherwise just assign right child even if its NULL
if (yNode->leftChild != NULL)
{
xNode = yNode->leftChild;
}
else
{
xNode = yNode->rightChild;
}
//assign xNode's parent as yNode if not NULL
if (xNode != NULL)
{
xNode->parent = yNode->parent;
}
parentNode = yNode->parent;
//if parent is false, we have the root
if (yNode->parent == NULL)
{
*Root = xNode;
}
//if y's parent leftChild, then we have the left child
//to delete
else if (yNode == yNode->parent->leftChild)
{
yNode->parent->leftChild = xNode;
leftNode = TRUE;
}
else
{
yNode->parent->rightChild = xNode;
leftNode = FALSE;
}
//make sure y and z are matching before the call
//to fixup
if (yNode != z)
{
z->key = yNode->key;
}
//if the node we deleted was black, call fix up.
//for a red node it doesnt matter
if (yNode->color == BLACK)
{
RBDeleteFixUp(Root, xNode, parentNode, leftNode);
}
}
bool RedBlackTree<T>::Remove(T item) {
Node<T>* x = NULL;
Node<T>* y = NULL;
Node<T>* z = getNodeFromTree(root, item); // The node to be removed (it's value
// will be gone, and it is going to be replaced
// by the predecessor's value if a predecessor exists
// for this node, and the predecessor's node will be
// deleted, or delete this node if no predecessor exists).
if (z == NULL) { // If no such item was found in the tree, then return false.
return false;
}
if (z->left == NULL || z->right == NULL) { // If z has at most one child.
y = z;
} else { // z has two children.
y = Predecessor(z);
}
if (y != NULL && y->left != NULL) { // The two conditions below are to
// find whether is y's only child
// is left or right.
x = y->left;
} else {
if (y != NULL) {
x = y->right;
}
}
bool xIsLeft = false;
Node<T>* xParent = NULL;
if (x != NULL && y != NULL) { // If x is not NULL, detach x from y.
x->p = y->p;
xParent = y->p;
}
if (y != NULL && y->p == NULL) { // Check if y is root (i.e. it has no parent).
root = x;
} else {
// Attach x to y's parent.
if (y == y->p->left) { // y is a left child.
y->p->left = x;
xIsLeft = true;
} else { // y is a right child.
y->p->right = x;
xIsLeft = false;
}
}
if (y != NULL && z != NULL && y != z) { // Check to see if y has been moved up.
z->data = y->data;
}
if (y != NULL && y->is_black == true) {
if (x == NULL) {
if (xParent == NULL) {
if (root != NULL && root->right != NULL && root->left != NULL && CalculateHeight(root->right) > CalculateHeight(root->left)) {
x = root->right;
xParent = root;
xIsLeft = false;
} else if (root != NULL && root->right != NULL && root->left != NULL && CalculateHeight(root->left) > CalculateHeight(root->right)) {
x = root->left;
xParent = root;
xIsLeft = true;
} else if (root != NULL && root->left == NULL) {
x = root->right;
xParent = root;
xIsLeft = false;
} else if (root != NULL && root->right == NULL) {
x = root->left;
xParent = root;
xIsLeft = true;
}
}
}
RBDeleteFixUp(x, xParent, xIsLeft);
}
delete y; // It can be the original predecessor's node, since its
// value has been moved up, or it can be z itself.
--size; // Decrement the size counter.
if (root != NULL && root->left != NULL && root->right == NULL) {
if (root->left->left == NULL && root->left->right == NULL) {
root->is_black = true;
root->left->is_black = false;
}
} else if (root != NULL && root->right != NULL && root->left == NULL) {
if (root->right->left == NULL && root->right->right == NULL) {
root->is_black = true;
root->right->is_black = false;
}
}
return true;
}
bool RedBlackTree<T>::Remove(T item) {
//if item not found return false
if (Search(item) == false) {
return false;
}
//Find the node z that has the value item
Node<T>*z = root;
while (z != NULL) {
if (item == z->data) {
break;
}
else if (item < z->data) {
z = z->left;
}
else {
z = z->right;
}
}
//item has at most one child
Node<T>* y;
Node<T>* x;
if (z->left == NULL || z->right == NULL) {
y = z;
}
else {
y = Predecessor(z);
}
if (y->left != NULL) {
x = y->left;
}
else {
x = y->right;
}
//x->p = y->p; cant do this because x could be NULL
//check if y is root, replace it by x
if (y->p == NULL) {
root = x;
}
else {
if (y == y->p->left) {
y->p->left = x;
}
else {
y->p->right = x;
}
//need to check x is not null ptr
if (x != NULL) {
x->p = y->p;
}
}
if (y != z) {
z->data = y->data;
}
if (y->is_black == true) {
if (x == y->p->left) {
RBDeleteFixUp(x, y->p, true);
}
//x is rightchold
else {
RBDeleteFixUp(x, y->p, false);
}
}
delete y;
size--;
return true;
}
