Mar 12, 2025 · In this article, we will explore how to implement a deque using a simple array. Insertions and deletions from both ends: You can add or remove elements from both ends of the deque. Fixed size: The size of the deque is fixed when the array is created.

Dec 10, 2015 · Deques support thread-safe, memory efficient appends and pops from either side of the deque with approximately the same O (1) performance in either direction.

Mar 12, 2025 · Deques can be implemented using arrays or linked lists, and they support operations like insertFront, insertRear, deleteFront and deleteRear efficiently. Insertion at Both Ends: You can insert elements at both the front and the rear, providing more flexibility compared to a standard queue.

Mar 6, 2025 · A deque stands for Double-Ended Queue. It is a data structure that allows adding and removing elements from both ends efficiently. Unlike regular queues, which are typically operated on using FIFO (First In, First Out) principles, a deque supports both FIFO and LIFO (Last In, First Out) operations.

Python’s deque is a low-level and highly optimized double-ended queue that’s useful for implementing elegant, efficient, and Pythonic queues and stacks, which are the most common list-like data types in computing. In this tutorial, you’ll learn: How …

The Python collections module provides an implementation of a deque. You can read the documentation here and the source code here . To confirm that it can add and remove elements from the beginning and end in constant time, let’s run some timing tests.

As for this problem, one feasible algorithm is to use deque: class RecentCounter: def __init__(self): . self.data = deque() def ping(self, t: int) -> int: while len(self.data) > 0 and (t - 3000) > self.data[0]: self.data.popleft() self.data.append(t) return len(self.data) 1 -1 mod n = n - 1.

Dec 16, 2019 · I used an integer mid to track the midpoint of the deque. This way elements can be inserted to the left or to the right appropriately. Here is a list of efficiencies according to Python's documentation for list. def __init__(self): self.array = [] self.mid = 0. def push_left(self, val): self.array.insert(self.mid, val) def push_right(self, val):

The ArrayDeque data structure allows for efficient addition and removal at both ends. This structure implements the List interface by using the same circular array technique used to represent an ArrayQueue. The and operations on an ArrayDeque are straightforward. They get or set the array element .

New items can be added at either the front or the rear. It is a hybrid linear structure provides all the capabilities of stacks and queues in a single data structure. Deque () creates a new deque that is empty. It needs no parameters and returns an empty deque. add_front (item) adds a new item to the front of the deque.