void p_queue::pop()
{
assert(size() > 0);
if(size() == 1)
{
--used;
return;
}
heap[0] = heap[used - 1];
used --;
size_type childIndex = 0;
size_type childPriority = 0;
size_type currentPriority = heap[0].priority;
while(is_leaf(childIndex) == false)
{
childPriority = big_child_priority(childIndex);
if(childPriority >= currentPriority)
{
childIndex = big_child_index(childIndex);
swap_with_parent(childIndex);
}
else
{
break;
}
}
}
p_queue::size_type
p_queue::big_child_priority(size_type i) const
// Pre: is_leaf(i) returns false
// Post: The priority of "the bigger child of the item at heap[i]"
// has been returned.
// (The bigger child is the one whose priority is no smaller
// than that of the other child, if there is one.)
{
assert( !is_leaf(i) );
size_type index = big_child_index(i);
return heap[index].priority;
}
void p_queue::pop()
{
assert(used > 0);
heap[0].data = heap[used - 1].data;
heap[0].priority = heap[used - 1].priority;
used--;
size_type i = 0;
while( !is_leaf(i) )
{
size_type index = big_child_index(i);
swap_with_parent(index);
i = index;
}
}
