Types of lists

The list as an ADT

• Common operations
  • create
  • test if empty
• LIFO (last-in/first-out) or stack operations
  • push new element
  • pop youngest element
• FIFO (first-in/first-out) or queue operations
  • enqueue new element
  • dequeue oldest element

The deque (or sometimes confusingly the dequeue) is a two-ended queue where elements can be removed and inserted on both ends.

In an priority queue elements are ordered by value.

Implementation

• Stack — singly linked list where elements are added and removed at a head node (5B-2)
• Queue — single linked list where elements are added at a head node and removed at a tail mode (5B-11)
• Deque — doubly linked list, perhaps with a dummy (5B-17)

Java Collections Framework

Interfaces

• Collection
• List
• Queue
• Deque

Implementations

• LinkedList
• ArrayList
• ArrayDeque

Four Deque methods

• addFirst or push
• removeFirst or pop
• addLast
• removeLast