PriorityQueue<T>.TrimExcess Method

This method can be used to minimize a collection's memory overhead if no new elements will be added to the collection. The cost of reallocating and copying a large PriorityQueue<T> can be considerable, however, so the TrimExcess() method does nothing if the list is at more than 90 percent of capacity. This avoids incurring a large reallocation cost for a relatively small gain.

Note
The current threshold of 90 percent it depends on List<T> and might change in future releases of the .Net Framework.

This method is an O(n) operation, where n is Count.

To reset a PriorityQueue<T> to its initial state, call the Clear() method before calling the TrimExcess() method. Trimming an empty PriorityQueue<T> sets the capacity of the PriorityQueue<T> to the default capacity.

The capacity can also be set using the Capacity property.

Reference