Deque

Class Deque is a double-ended queue, which is a data structure that allows insertion and deletion of elements from both ends. It is a generalization of the queue data structure.

Class

• Deque(): creates a new empty deque.

Methods

• clear(): removes all elements from the deque.
• isEmpty(): returns true if the deque is empty, false otherwise.
• iterator(): returns an iterator to traverse the elements in the deque.
• peekBack(): returns the element at the back of the deque without removing it.
• peekFront(): returns the element at the front of the deque without removing it.
• popBack(): removes and returns the element at the back of the deque.
• popFront(): removes and returns the element at the front of the deque.
• print(): prints all elements in the deque.
• pushBack(value): adds an element to the back of the deque.
• pushFront(value): adds an element to the front of the deque.
• size(): returns the number of elements in the deque.
• toArray(): returns an array containing all elements in the deque.

Usage

JavaScript

import { Deque } from "dsacjs";

const deque = new Deque();

deque.pushBack(1);
deque.pushBack(2);
deque.pushBack(3);

console.log(deque.toArray()); // [1, 2, 3]

deque.popFront();
deque.popBack();

console.log(deque.toArray()); // [2]

TypeScript

import { Deque } from "dsacjs";

const deque = new Deque<number>();

deque.pushBack(1);
deque.pushBack(2);
deque.pushBack(3);

console.log(deque.toArray()); // [1, 2, 3]

deque.popFront();
deque.popBack();

console.log(deque.toArray()); // [2]

Time Complexity

• clear(): O(1)
• isEmpty(): O(1)
• peekBack(): O(1)
• peekFront(): O(1)
• popBack(): O(1)
• popFront(): O(1)
• print(): O(n)
• pushBack(value): O(1)
• pushFront(value): O(1)
• size(): O(1)
• toArray(): O(n)