/**
* @brief If sibling is black and its both children are black, perform recoloring.
* @param t is the tree root.
* @param n is the node at which deletion is taking place.
*/
void delete_case4(rbtree t, node n)
{
if (node_color(n->parent) == RED && node_color(sibling(n)) == BLACK && node_color(sibling(n)->left) == BLACK && node_color(sibling(n)->right) == BLACK)
{
sibling(n)->color = RED;
n->parent->color = BLACK;
}
else
delete_case5(t, n);
}
static void delete_case4(L_RBTREE *t, node *n) {
if (node_color(n->parent) == L_RED_NODE &&
node_color(sibling(n)) == L_BLACK_NODE &&
node_color(sibling(n)->left) == L_BLACK_NODE &&
node_color(sibling(n)->right) == L_BLACK_NODE) {
sibling(n)->color = L_RED_NODE;
n->parent->color = L_BLACK_NODE;
} else {
delete_case5(t, n);
}
}
void delete_case4(struct rbtree* t, struct rbtree_node* n)
{
if (get_color(n->parent) == RB_RED &&
get_color(sibling(n)) ==RB_BLACK &&
get_color(sibling(n)->left) ==RB_BLACK &&
get_color(sibling(n)->right) == RB_BLACK)
{
sibling(n)->color =RB_RED; //sibling's two son is black ,so it can changed to red
n->parent->color = RB_BLACK;
}
else
delete_case5(t, n);
}
void delete_case4(rb_node* n, rb_tree* tree) {
rb_node* s = sibling(n);
if ((n->parent->color == RED) &&
(s->color == BLACK) &&
(s->left->color == BLACK) &&
(s->right->color == BLACK)) {
s->color = RED;
n->parent->color = BLACK;
} else {
delete_case5(n, tree);
}
}
static inline void
delete_case4(struct RBTREE_TYPENAME* target, struct RBTREE_NODE* P,
struct RBTREE_NODE* N, struct RBTREE_NODE* S)
{
if ((P->color == RED) &&
(S->color == BLACK) &&
(S->left == NULL || S->left->color == BLACK) &&
(S->right == NULL || S->right->color == BLACK))
{
S->color = RED;
P->color = BLACK;
}
else
delete_case5(target, P, N, S);
}
void Tree::delete_case4()
{
//if parent is red and siblings family is black
//we add another black to current nodes path by making parent red
//and removing a black from siblings path
if(parent->red && !(sibling()->red) &&
!(sibling()->left->red) && !(sibling()->right->red))
{
sibling()->red = true;
parent->red = false;
return;
}
else
delete_case5();
}