/* delete min value. multi-pass */
void heap_delete_min(heap *hp) {
heap_node *a,*b,*next_tmp,*new_root=NULL;
heap_node * h = hp->root;
/* until there is one node */
/* heap_node_meld in pairs, 1st and 2nd, 3rd and 4th, ...*/
while(h->first_child!=h->last_child) {
a = h->first_child;
while(a!=NULL)
{
next_tmp=NULL;
b = a->next_sibling;
heap_node_isolate(a);
if (b) {
next_tmp=b->next_sibling;
heap_node_isolate(b);
a = heap_node_meld(a,b);
}
h = heap_node_meld(h,a);
a = next_tmp;
}
}
if (h->first_child) {
new_root = h->first_child;
h->first_child->parent=NULL;
}
free(h);
hp->root = new_root;
}
/* delete min value. classic two-pass */
void heap_delete_min(heap *hp) {
heap_node *a,*b,*next_tmp,*new_root=NULL,*h;
heap_combine(hp);
h = hp->root;
/* two-pass merge */
/* heap_node_link in pairs, 1st and 2nd, 3rd and 4th, ...*/
a = h->first_child;
while(a!=NULL)
{
next_tmp=NULL;
b = a->next_sibling;
heap_node_isolate(a);
if (b) {
next_tmp=b->next_sibling;
heap_node_isolate(b);
a = heap_node_link(a,b);
}
h = heap_node_link(h,a);
a = next_tmp;
}
/* attach all to the oldest one */
a = h->first_child;
while(a!=NULL)
{
b = a->next_sibling;
if (!b) break;
heap_node_isolate(a);
heap_node_isolate(b);
a = heap_node_link(a,b);
h = heap_node_link(h,a);
}
if (h->first_child) {
new_root = h->first_child;
h->first_child->parent=NULL;
}
free(h);
hp->n_elements--;
hp->root = new_root;
hp->minimum= new_root;
}
/* decrease the value of the node */
void heap_decrease_key(heap *h, heap_node *node, int delta) {
heap_node *node_first_child;
node->value -= delta;
if (node->value < h->minimum->value) {
h->minimum = node;
}
/* left most sub child takes place of node */
if (node!=h->root) {
node_first_child = node->first_child;
if (node_first_child) {
heap_node_isolate(node_first_child);
node->first_child->parent = node->parent;
node->first_child->next_sibling = node->next_sibling;
node->first_child->previous_sibling = node->previous_sibling;
if (node->next_sibling) {
node->next_sibling->previous_sibling = node_first_child;
} else {
node->parent->last_child = node_first_child;
}
if (node->previous_sibling) {
node->previous_sibling->next_sibling = node_first_child;
} else {
node->parent->first_child = node_first_child;
}
} else {
heap_node_isolate(node);
}
}
/* add the rest of node's subtrees to the pool as standalone trees */
while (node->first_child) {
h->pool[h->pool_size++] = node->first_child;
heap_node_isolate(node->first_child);
}
if (h->pool_size>=log2(h->n_elements))
heap_combine(h);
}
/* decrease the value of the node */
void heap_decrease_key(heap *h, heap_node *node, int delta) {
node->value -= delta;
/* if the node is not at the root of the tree, remove it and
merge it with the root */
if (node!=h->root) {
/* remove the node tree from the siblings and parents*/
heap_node_isolate(node);
/* merge with root*/
h->root = heap_node_meld(h->root,node);
}
}
/* decrease the value of the node */
void heap_decrease_key(heap_node *node, foi new_weight) {
node->value.weight = new_weight;
/* if the node is not at the root of the tree, remove it and
merge it with the root */
if (node!=hp->root) {
/* remove the node tree from the siblings and parents*/
heap_node_isolate(node);
/* merge with root*/
hp->root = heap_node_meld(hp->root,node);
}
}
