element delete_max_heap(int *n)
{
/* delete element with the highest key from heap */
int parent, child; // variables of key
element item, temp;
if (HEAP_EMPTY(*n))
{
fprintf(stderr, "The heap is empty.\n");
exit(EXIT_FAILURE);
}
/* save value of the element with the highest key */
item = heap[1];
temp = heap[(*n)--];
parent = 1;
child = 2;
while (child <= *n)
{
/* find the larger child of the current paren */
if ((child < *n) && (heap[child].key < heap[child+1].key))
child++;
/* move to next lower level */
if (temp.key >= heap[child].key)
break;
heap[parent] = heap[child];
parent =child;
child *= 2;
}
heap[parent] = temp;
return item;
}
struct heap_t *heap_max_delete (struct heap_h *h)
{
int parent, child;
struct heap_t *item, *temp;
if (HEAP_EMPTY (h))
return NULL;
item = (h->p + 1);
temp = (h->p + (h->cnt)--);
parent = 1;
child = 2;
while (child <= h->cnt)
{
if ((child < h->cnt) && ((h->p + child)->key < (h->p + child + 1)->key))
child++;
if (temp->key >= (h->p + child)->key)
break;
memcpy (h->p + parent, h->p + child, sizeof (struct heap_t));
parent = child;
child *= 2;
}
memcpy (h->p + parent, temp, sizeof (struct heap_t));
return item;
}
