Data Structures

Question 1

What does the acronym LIFO mean?

Answer 1

last-in-first-out

Question 2

What methods are available on a Stack data structure?

Answer 2

push(value) - adds a value to the “top” of the stack
pop() - removes the top value from the stack and returns it
peek() - returns the “top” value of the stack without removing it.

Question 3

What must you do to access the value at an arbitrary point in a stack (not just the “top”)?

Answer 3

pop() and peek() until you reach that point

Question 4

What does the acronym FIFO mean?

Answer 4

First In First Out

Question 5

What methods are available on a Queue data structure?

Answer 5

enqueue(value) - adds a value to the “back” of the queue

dequeue() - removes the “front” value from the queue and returns it

peek() - peeks the “front” value without modifying the queue

Question 6

What must you do to access the value at an arbitrary point in a queue (not just the “front”)?

Answer 6

Dequeue until you reach desired value

Question 7

How are linked lists different from an array?

Answer 7

Linked lists are sequential access, where as arrays are random access

Does not need to be mutated to scan it’s contents (queue needs to be mutated)

Question 8

How would you access an arbitrary node in a linked list (not just the “head”)?

Answer 8

Start at the head and traverse through with the next property

Question 9

What methods are available on linked lists?

Answer 9

.data - contains the node’s value.

.next a reference to the next node in the list, if there is one. If there is no “next” node in the list, this property is typically set to null.