// Remove a node at a particular position in the queue.
private PriorityQueueItem <TValue> RemoveAt(Int32 index)
{
// remove an item from the heap
PriorityQueueItem <TValue> o = items[index];
PriorityQueueItem <TValue> tmp = items[numItems - 1];
items[--numItems] = default(PriorityQueueItem <TValue>);
if (numItems > 0)
{
int i = index;
int j = i + 1;
while (i < Count / 2)
{
if ((j < Count - 1) && (items[j].Priority > items[j + 1].Priority))
{
j++;
}
if (items[j].Priority >= tmp.Priority)
{
break;
}
items[i] = items[j];
i = j;
j *= 2;
}
items[i] = tmp;
}
return(o);
}
/// <summary>
/// Copies the queue elements to a new array.
/// </summary>
/// <returns>A new array containing elements copied from the Queue.</returns>
public PriorityQueueItem <TValue>[] ToArray()
{
PriorityQueueItem <TValue>[] newItems =
new PriorityQueueItem <TValue> [numItems];
Array.Copy(items, newItems, numItems);
return(newItems);
}
/// <summary>
/// Adds an object to the queue, in order by priority.
/// </summary>
/// <param name="value">The object to be added.</param>
/// <param name="priority">Priority of the object to be added.</param>
public void Enqueue(TValue value, int priority)
{
if (numItems == capacity)
{
// need to increase capacity
// grow by 50 percent
SetCapacity((3 * Capacity) / 2);
}
// Create the new item
PriorityQueueItem <TValue> newItem =
new PriorityQueueItem <TValue>(value, priority);
int i = numItems;
++numItems;
// and insert it into the heap.
while ((i > 0) && (items[i / 2].Priority > newItem.Priority))
{
items[i] = items[i / 2];
i /= 2;
}
items[i] = newItem;
}