/// <summary>
/// Uses Equality check only for removing from the queue.
/// Might cost O(n) if all items are in the queue and not the heap.
/// </summary>
/// <param name="item"></param>
/// <returns></returns>
public bool Remove
(
IBinaryHeapItem item
)
{
if (item.GetIndexInHeap() == BinaryHeap.REMOVED_FROM_HEAP) // Or from queue.
{
return(false);
}
bool removedFromQueue = false;
// Remove from the queue if it's there, keeping the order in the queue.
for (int i = 0; i < this.queue.Count; ++i)
{
IBinaryHeapItem temp = this.queue.Dequeue();
if (temp.Equals(item))
{
removedFromQueue = true;
temp.SetIndexInHeap(BinaryHeap.REMOVED_FROM_HEAP);
}
else
{
this.queue.Enqueue(temp);
}
}
if (removedFromQueue == true)
{
return(true);
}
return(this.heap.Remove(item));
}
/// <summary>
/// Adds a key and value to the heap.
/// </summary>
/// <param name="item">The item to add to the heap.</param>
public void Add(IBinaryHeapItem item)
{
if (item == null)
{
return;
}
if (_count == _capacity)
{
Capacity *= 2; // Automatically grows the array!
}
item.SetIndexInHeap(_count);
_data[_count] = item;
_count++;
UpHeap();
}
/// <summary>
/// Removes and returns the first item in the heap.
/// </summary>
/// <returns>The next item in the heap.</returns>
public IBinaryHeapItem Remove()
{
if (this._count == 0)
{
throw new InvalidOperationException("Cannot remove item, heap is empty.");
}
IBinaryHeapItem v = _data[0];
v.SetIndexInHeap(REMOVED_FROM_HEAP);
_count--;
if (this._count != 0)
{
_data[0] = _data[_count];
DownHeap();
}
_data[_count] = default(IBinaryHeapItem); // Clear the last node
return(v);
}