Explain What is the worst case complexity of accessing an element in ArrayList?

Question

What is the worst case complexity of accessing an element in ArrayList? (a) O(n) (b) O(1) (c) O(nlogn) (d) O(2) This question was posed to me in a job interview. This interesting question is from Data Structures-List in section java.util – The Collections Framework of Java Select the correct answer from above options

Answer 1

Right option is (b) O(1) To explain I would say: ArrayList has O(1) complexity for accessing an element in ArrayList. O(n) is the complexity for accessing an element from LinkedList.