Example #1
0
        private PriorityQueueItem <TValue, TPriority> RemoveAt(Int32 index)
        {
            PriorityQueueItem <TValue, TPriority> o = items[index];

            --numItems;
            // move the last item to fill the hole
            PriorityQueueItem <TValue, TPriority> tmp = items[numItems];

            // If you forget to clear this, you have a potential memory leak.
            items[numItems] = default(PriorityQueueItem <TValue, TPriority>);
            if (numItems > 0 && index != numItems)
            {
                // If the new item is greater than its parent, bubble up.
                int i      = index;
                int parent = (i - 1) / 2;
                while (compareFunc(tmp.Priority, items[parent].Priority) > 0)
                {
                    items[i] = items[parent];
                    i        = parent;
                    parent   = (i - 1) / 2;
                }

                // if i == index, then we didn't move the item up
                if (i == index)
                {
                    // bubble down ...
                    while (i < (numItems) / 2)
                    {
                        int j = (2 * i) + 1;
                        if ((j < numItems - 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;
                    }
                }
                // Be sure to store the item in its place.
                items[i] = tmp;
            }
            //if (!VerifyQueue())
            //{
            //    Console.WriteLine("ERROR: Queue out of order!");
            //}
            return(o);
        }
Example #2
0
        public void Enqueue(PriorityQueueItem <TValue, TPriority> newItem)
        {
            if (numItems == capacity)
            {
                // need to increase capacity
                // grow by 50 percent
                SetCapacity((3 * Capacity) / 2);
            }

            int i = numItems;

            ++numItems;
            while ((i > 0) && (compareFunc(items[(i - 1) / 2].Priority, newItem.Priority) < 0))
            {
                items[i] = items[(i - 1) / 2];
                i        = (i - 1) / 2;
            }
            items[i] = newItem;
            //if (!VerifyQueue())
            //{
            //    Console.WriteLine("ERROR: Queue out of order!");
            //}
        }