The interview process consisted of one coding round on HackerEarth, followed by three technical interviews.

I took the coding test in February and received an interview invitation in May. They were specifically looking for Java developers in February, and as I wasn't, my interviews were delayed. I received the test link by applying through their jobs portal.

PayPal Experience for 1.2 Years Experienced

Round 1

Problem: Linked List Given a single Linked List, you need to swap the first and last elements in the list.

Problem: Given an unsorted array, find the kth smallest element. I/p: [1, 4, 5, 6, 3, 3, 8] k: 3 o/p: 4

Problem: Pattern Matching IP: String: 10000100000010010 Regex: 10*1 o/p: 3

Round 2

Problem: For each element, find the distance to the next greater element on its right. Array: [73, 72, 89, 76, 71, 67, 62, 61, 82, 90, 12] Indices: 0 1 2 3 4 5 6 7 8 9 10 Result: [2, 1, 7, 5, 4, 3, 2, 1, 1, -1, -1]

Problem: Merge two sorted linked lists. List 1: 1 -> 2 -> 3 -> 4 -> 5 List 2: 2 -> 5 -> 15 -> 19

Problem: Merge lists of sorted linked lists. [ [1, 2, 3, 4], [2, 3, 4, 5], [4, 5, 6, 7], [7, 8, 9, 10] ]

Round 3 (with hiring manager)

Problem: Create a Binary Tree from a given list and print its level order traversal (nulls are denoted as 0). Input: 7, 3, 9, 20, 0, 0, 15, 7

Problem: Design a system. There are three buttons on the screen, clicked randomly. At any instant, find the total clicks for the past 1, 2, or 3 hours, minutes, or days for any button.