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(), which returns the “top” value of the stack without removing it.
print(), which prints the values in the stack

Question 3

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

Answer 3

you can pop them in a placeholder variable then push them back in order

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(), which returns the “front” value of the queue without removing it.

Question 6

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

Answer 6

you can keep dequeue until you get to the arbitrary point

Question 7

How are linked lists different from an array?

Answer 7

linked lists are sequential access (like a queue), not random access (like an array)
arrays constant time

Question 8

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

Answer 8

use the next method until you do get to the arbitrary point