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Queue overflow results from trying to add an element onto a full queue and queue underflow happens when trying to remove an element from an empty queue. A bounded queue is a queue limited to a fixed number of items. [1] There are several efficient implementations of FIFO queues.
Push-Pop(heap: List<T>, item: T) -> T: if heap is not empty and heap[1] > item then: // < if min heap swap heap[1] and item _downheap(heap starting from index 1) return item. A similar function can be defined for popping and then inserting, which in Python is called "heapreplace":
The d-ary heap consists of an array of n items, each of which has a priority associated with it. These items may be viewed as the nodes in a complete d-ary tree, listed in breadth first traversal order: the item at position 0 of the array (using zero-based numbering) forms the root of the tree, the items at positions 1 through d are its children, the next d 2 items are its grandchildren, etc.
A double-ended queue can be used to store the browsing history: new websites are added to the end of the queue, while the oldest entries will be deleted when the history is too large. When a user asks to clear the browsing history for the past hour, the most recently added entries are removed.
The semantics of priority queues naturally suggest a sorting method: insert all the elements to be sorted into a priority queue, and sequentially remove them; they will come out in sorted order. This is actually the procedure used by several sorting algorithms , once the layer of abstraction provided by the priority queue is removed.
The principal benefit of a linked list over a conventional array is that the list elements can be easily inserted or removed without reallocation or reorganization of the entire structure because the data items do not need to be stored contiguously in memory or on disk, while restructuring an array at run-time is a much more expensive operation ...
Here is a simple example of how coroutines can be useful. Suppose you have a consumer-producer relationship where one routine creates items and adds them to a queue and another removes items from the queue and uses them. For reasons of efficiency, you want to add and remove several items at once. The code might look like this:
As all non-constant-time operations are defined in terms of the Meld operation, the efficiency of these operations can be determined through analysis of the complexity of melding two randomized heaps. The result of this analysis is that the expected time of any meldable priority queue operation on a n-node randomized heap is O(logn). [1] [2]