Arrays

Question 1

Show me how to initialize a regular array

Answer 1

int[] array = new int[5]
5 being the size

Question 2

Show me how to initialize a array list

Answer 2

import java.util.ArrayList;

ArrayList<Integer> array = new ArrayList<>();</Integer>

Question 3

Array Add to End Complexity

Answer 3

O(1)

Question 4

Iterate through the Array complexity (search)

Answer 4

O(n)

Question 5

Insert at begining and elsewhere in the array Complexity

Answer 5

O(n)

Question 6

Delete and access elements at Index x

Answer 6

O(1)

Question 7

How would you reverse an array?

Answer 7

Have a pointer at the start and end of the array, then loop through incrementing start then decrementing end making sure that they switch variables

While start < end
- temp value stores start
- start value = end value
- end value = temp value
- increment start
- decrement end, repeat

Question 8

Difference between an array and an arraylist

Answer 8

Arrays have a set size
Arraylists are dynamic