Queue

const  DoublyLinkedList = require('./DoublyLinkedList.js');

class Queue {
    constructor() {
        this.dll = new DoublyLinkedList();
    }

    isEmpty() {
        return this.size() === 0;
    }

    getFront() {
        return this.isEmpty() ? null : this.dll.getHead();
    }

    getTail() {
        return this.isEmpty() ? null : this.dll.getTail();
    }

    size() {
        return this.dll.size();
    }

    // Add an item to the queue (Time complexity: O(1))
    enqueue(value) {
        return this.dll.insertTail(value);
    }

    // Remove an item from the queue (Time complexity: O(1))
    dequeue() {
        return this.dll.removeHead();
    }
}

const queue = new Queue();

Operation	Time Complexity
isEmpty	O(1)
getFront	O(1)
getTail	O(1)
size	O(1)
enqueue	O(1)
dequeue	O(1)

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