Swift Data Structure and Algorithms

Queue

A queue is a First In First Out (FIFO) data structure. To visualize a FIFO, imagine you're standing in line for the checkout at the grocery store. When the first person (head) in line reaches the cashier, she rings up their purchases, they pay and collect their groceries and leave (pop); the second person in line is now first in line, and we repeat the process.

When a new customer stands (push) in line behind the last person in line, they are now in the tail position.

Queue data structure

A queue implements the following seven operations:

• enqueue() - Adds an element to the back of the queue
• dequeue() - Removes and returns the first element from ...