//use predecessor instead of successor
void
Tree_Delete_v2 (
NODE **root,
NODE *z
)
{
NODE *y;
if (!z->left) {
//either z->right is null (no child)
//or z->right only (replace z with z->right)
printf ("case 1:\n");
Transplant (root, z, z->right);
} else if (!z->right) {
//z->left only, replace z with z->left
printf ("case 2:\n");
Transplant (root, z, z->left);
} else {
//both z->right and z->left are valid
y = Tree_Predecessor (z);
printf ("Predecessor of %d is:\n", z->key);
Print_Node (y);
if (y != z->left) {
//replace y with y->left
//y has no right child
Transplant (root, y, y->left);
y->left = z->left;
z->left->p = y;
}
//if y == z->left, replace z with y directly
Transplant (root, z, y);
y->right = z->right;
z->right->p = y;
}
}
void BST :: BSTdelete( NodePtr z )
{
NodePtr y ;
if(z->left==NIL)
{
Transplant(z,z->right);
}
else if(z->right==NIL)
{
Transplant(z,z->left);
}
else
{
y = BSTminimum(z->right);
if(y->p != z)
{
Transplant(y,y->right);
y->right = z->right;
y->right->p=y;
}
Transplant(z,y);
y->left=z->left;
y->left->p = y;
}
// You write the rest of this
}
void
Tree_Delete (
NODE **root,
NODE *z
)
{
NODE *y;
if (!z->left) {
//either z->right is null (no child)
//or z->right only (replace z with z->right)
printf ("case 1:\n");
Transplant (root, z, z->right);
} else if (!z->right) {
//z->left only, replace z with z->left
printf ("case 2:\n");
Transplant (root, z, z->left);
} else {
//z->left and z->right are valid,
//find successor(z):
y = Tree_Successor (z); //y must in the right subtree of z
printf ("successor of %d is:\n", z->key);
Print_Node (y);
// //for debug
// if (y) {
// printf ("successor: key = %d, p = 0x%x, left = 0x%x, right = 0x%x\n",
// y->key, (int)(y->p), (int)(y->left), (int)(y->right));
// if (y->p) {
// printf ("p = %d, ", y->p->key);
// }
// if (y->left) {
// printf ("left = %d, ", y->left->key);
// }
// if (y->right) {
// printf ("right = %d, ", y->right->key);
// }
// printf ("\n");
// } else {
// printf ("successor: not found.\n");
// }
//and y has no left childs !!
if (y->p != z) {
printf ("case 3:\n");
//replace y with y->right
//update childs manually:
//Transplant () updates parents only
Transplant (root, y, y->right);
y->right = z->right;
z->right->p = y;
}
printf ("case 4:\n");
//if y == z->right, replace z with y directly
Transplant (root, z, y);
//z has left childs, update their parents
y->left = z->left;
z->left->p = y;
}
}
void RedBlackTree::Delete(uint32_t key)
{
RedBlackNode::Ptr z = Search(key);
RedBlackNode::Ptr x;
if(z == nil)
return;
RedBlackNode::Ptr y = z;
RedBlackNode::color_t original_color = y->Color();
if(z->Left() == nil)
{
x = z->Right();
Transplant(z,z->Right());
}
else if(z->Right() == nil)
{
x = z->Left();
Transplant(z,z->Left());
}
else
{
y = Minimum(z->Right());
original_color = y->Color();
x = y->Right();
if(y->Parent() == z)
{
x->Parent(y);
}
else
{
Transplant(y,y->Right());
y->Right(z->Right());
y->Right()->Parent(y);
}
Transplant(z,y);
y->Left(z->Left());
y->Left()->Parent(y);
y->Color(z->Color());
}
if(original_color == RedBlackNode::BLACK)
{
Delete_Fixup(x);
}
}
