// Remove a node at a particular position in the queue.
private PriorityQueueItem <TValue, TPriority> RemoveAt(Int32 index)
{
// remove an item from the heap
PriorityQueueItem <TValue, TPriority> o = items[index];
PriorityQueueItem <TValue, TPriority> tmp = items[numItems - 1];
items[--numItems] = default(PriorityQueueItem <TValue, TPriority>);
if (numItems > 0)
{
int i = index;
int j = i + 1;
while (i < Count / 2)
{
if ((j < Count - 1) && (compareFunc(items[j].Priority, items[j + 1].Priority) < 0))
{
j++;
}
if (compareFunc(items[j].Priority, tmp.Priority) <= 0)
{
break;
}
items[i] = items[j];
i = j;
j *= 2;
}
items[i] = tmp;
}
return(o);
}
public TValue Dequeue(out TPriority prio)
{
if (Count == 0)
{
throw new InvalidOperationException("The queue is empty");
}
PriorityQueueItem <TValue, TPriority> item = RemoveAt(0);
prio = item.Priority;
return(item.Value);
}
public void Enqueue(TValue value, TPriority priority)
{
if (numItems == capacity)
{
// need to increase capacity
// grow by 50 percent
SetCapacity((3 * Capacity) / 2);
}
// Create the new item
var newItem =
new PriorityQueueItem <TValue, TPriority>(value, priority);
int i = numItems;
++numItems;
// and insert it into the heap.
while ((i > 0) && (compareFunc(items[i / 2].Priority, newItem.Priority) < 0))
{
items[i] = items[i / 2];
i /= 2;
}
items[i] = newItem;
}
