today i'm going to teach you about cues cues are an elementary data structure that represent a dynamic set of data we insert and delete elements into a queue but the delete operation is done in a predefined manner for cues this is called fifo or first in first out we call the insert method in queue and the delete method dq dq takes no arguments let's look at an example here's what we use to represent our queue i've marked the front and the back you'll see later in our python example that we'll implement this with collections.dq which is a doubly linked list this allows us to enqueue and dequeue in constant time we'll insert elements at the back of the queue and remove them from the front we start with an empty cue and insert the element one it's added at the back but because the cue is empty it's first in line let's add a few more elements two and three notice two and three are added at the back behind the element one we dequeue our first element removing one which was the first element added to the queue pretty simple i'll let the rest of the example play without voiceover lastly let's look at the code which is shown in python and linked in the description we'll use collections.dq as our queue and implement the inque and dq method for enqueue we simply append the element to the end for dq we call pop left which removes the element at the front of the queue because collections.dq is represented internally as a doubly linked list this operation is achieved in constant time as is in queue in computing cues have numerous uses operating systems use them extensively for cpu and disk scheduling when you swipe right on a song in spotify you're adding it to a queue and if you've watched my other videos you've seen we've used cues to implement breadth first search thank you for watching i hope this video helps you on your computer science journey please like and subscribe