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The dynamic array approach uses a variant of a dynamic array that can grow from both ends, sometimes called array deques. These array deques have all the properties of a dynamic array, such as constant-time random access , good locality of reference , and inefficient insertion/removal in the middle, with the addition of amortized constant-time ...
For example, Perl and Ruby allow pushing and popping an array from both ends, so one can use push and shift functions to enqueue and dequeue a list (or, in reverse, one can use unshift and pop), [2] although in some cases these operations are not efficient.
Behavior when the collection is empty varies – most often this yields an underflow error, identically to a pop on an empty collection, but some implementations provide a function which instead simply returns (without error), essentially implementing if isempty then return, else peek. This behavior can be axiomatized in various ways.
STL also has utility functions for manipulating another random-access container as a binary max-heap. The Boost libraries also have an implementation in the library heap. Python's heapq module implements a binary min-heap on top of a list. Java's library contains a PriorityQueue class, which implements a min-priority-queue as a binary heap.
Min-max heaps are often represented implicitly in an array; [4] hence it's referred to as an implicit data structure. The min-max heap property is: each node at an even level in the tree is less than all of its descendants, while each node at an odd level in the tree is greater than all of its descendants .
In computer science, the word dequeue can be used as: A verb meaning "to remove from a queue" An abbreviation for double-ended queue (more commonly, deque
If the array contains all non-negative numbers, then the problem is trivial; a maximum subarray is the entire array. If the array contains all non-positive numbers, then a solution is any subarray of size 1 containing the maximal value of the array (or the empty subarray, if it is permitted).
A similar function can be defined for popping and then inserting, which in Python is called "heapreplace": // Extract the root of the heap, and push a new item // heap : an array representing the heap, indexed at 1 // item : an element to insert // Returns the current root of heap Replace ( heap : List<T>, item : T) -> T: swap heap [1] and item ...