1. Doubly linked lists
Idea: same as singly linked list, but each node also points to the previous:
Can optionally also have a pointer to the tail, so we can start scanning from the end, and make appending easier
Also helps with binary search

2. Inserting into a DLL Find node before the new one, nextNode
Set newNode.prev = nextNode.prev
Set newNode.prev.next = newNode
Set newNode.next = nextNode
Set nextNode.prev = newNode

3. Queues
Main idea: similar to a stack, but use “First in, first out” methodology
”Push” and “Pop” now become “enqueue” and “dequeue”
Primary stipulation: dequeue returns the least-recently enqueued item