rbtree_node_t *rbtree_remove(rbtree_t *tree, rbtree_node_t *node) { rbtree_node_t *remove, *child; if (node->left == tree->sentinel || node->right == tree->sentinel) remove = node; else remove = rbtree_successor(tree, node); if (remove->left != tree->sentinel) child = remove->left; else child = remove->right; child->parent = remove->parent; if (remove->parent == tree->sentinel) tree->root = child; else if (remove == remove->parent->left) remove->parent->left = child; else remove->parent->right = child; if (remove != node) { node->key = remove->key; } if (rbtree_is_black(remove)) rbtree_remove_fixup(tree, child); rbtree_node_delete(remove); return node; }
static void _rbtree_print(rbtree_t *tree, rbtree_node_t *node) { if (node != tree->sentinel) { _rbtree_print(tree, node->left); printf("%d[%c] ", node->key, rbtree_is_black(node) ? 'b' : 'r'); _rbtree_print(tree, node->right); } }
static void rbtree_remove_fixup(rbtree_t *tree, rbtree_node_t *node) { rbtree_node_t *brother; while (node != tree->root && rbtree_is_black(node)) { if (node == node->parent->left) { brother = node->parent->right; if (rbtree_is_red(brother)) { rbtree_color_swap(node->parent, brother); rbtree_left_rotate(tree, node->parent); brother = node->parent->right; } if (rbtree_is_black(brother->left) && rbtree_is_black(brother->right)) { rbtree_set_red(brother); node = node->parent; } else { if (rbtree_is_black(brother->right)) { rbtree_color_swap(brother, brother->left); rbtree_right_rotate(tree, brother); brother = node->parent->right; } rbtree_set_black(brother->right); rbtree_color_swap(node->parent, brother); rbtree_left_rotate(tree, node->parent); node = tree->root; } } else { brother = node->parent->left; if (rbtree_is_red(brother)) { rbtree_color_swap(node->parent, brother); rbtree_right_rotate(tree, node->parent); brother = node->parent->left; } if (rbtree_is_black(brother->left) && rbtree_is_black(brother->right)) { rbtree_set_red(brother); node = node->parent; } else { if (rbtree_is_black(brother->left)) { rbtree_color_swap(brother, brother->right); rbtree_left_rotate(tree, brother); brother = node->parent->left; } rbtree_set_black(brother->left); rbtree_color_swap(node->parent, brother); rbtree_right_rotate(tree, node->parent); node = tree->root; } } } rbtree_set_black(node); }
void rbtree_delete(struct rbtree *tree, struct rbnode *node) { struct rbnode **root = &tree->root; struct rbnode *sentinel = tree->sentinel; struct rbnode *subst, *temp, *w; uint8_t red; /* a binary tree delete */ if (node->left == sentinel) { temp = node->right; subst = node; } else if (node->right == sentinel) { temp = node->left; subst = node; } else { subst = rbtree_node_min(node->right, sentinel); if (subst->left != sentinel) { temp = subst->left; } else { temp = subst->right; } } if (subst == *root) { *root = temp; rbtree_black(temp); rbtree_node_init(node); return; } red = rbtree_is_red(subst); if (subst == subst->parent->left) { subst->parent->left = temp; } else { subst->parent->right = temp; } if (subst == node) { temp->parent = subst->parent; } else { if (subst->parent == node) { temp->parent = subst; } else { temp->parent = subst->parent; } subst->left = node->left; subst->right = node->right; subst->parent = node->parent; rbtree_copy_color(subst, node); if (node == *root) { *root = subst; } else { if (node == node->parent->left) { node->parent->left = subst; } else { node->parent->right = subst; } } if (subst->left != sentinel) { subst->left->parent = subst; } if (subst->right != sentinel) { subst->right->parent = subst; } } rbtree_node_init(node); if (red) { return; } /* a delete fixup */ while (temp != *root && rbtree_is_black(temp)) { if (temp == temp->parent->left) { w = temp->parent->right; if (rbtree_is_red(w)) { rbtree_black(w); rbtree_red(temp->parent); rbtree_left_rotate(root, sentinel, temp->parent); w = temp->parent->right; } if (rbtree_is_black(w->left) && rbtree_is_black(w->right)) { rbtree_red(w); temp = temp->parent; } else { if (rbtree_is_black(w->right)) { rbtree_black(w->left); rbtree_red(w); rbtree_right_rotate(root, sentinel, w); w = temp->parent->right; } rbtree_copy_color(w, temp->parent); rbtree_black(temp->parent); rbtree_black(w->right); rbtree_left_rotate(root, sentinel, temp->parent); temp = *root; } } else { w = temp->parent->left; if (rbtree_is_red(w)) { rbtree_black(w); rbtree_red(temp->parent); rbtree_right_rotate(root, sentinel, temp->parent); w = temp->parent->left; } if (rbtree_is_black(w->left) && rbtree_is_black(w->right)) { rbtree_red(w); temp = temp->parent; } else { if (rbtree_is_black(w->left)) { rbtree_black(w->right); rbtree_red(w); rbtree_left_rotate(root, sentinel, w); w = temp->parent->left; } rbtree_copy_color(w, temp->parent); rbtree_black(temp->parent); rbtree_black(w->left); rbtree_right_rotate(root, sentinel, temp->parent); temp = *root; } } } rbtree_black(temp); }