PayPal Software Development Engineer (SDE) II interview questions

General leet code or Hackerrank rounds

Paypal Experience for 1.2 years Experienced Round 1 Problem: LinkedList Given a single Linked list, you need to swap the first and last element in the list. Problem: Given an unsorted array, you need to 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 the right of it. array [73, 72, 89, 76 , 71, 67, 62, 61, 82 , 90 , 12] indices 0 1 2 3 4 5 6 7 8 9 10 resulut [2, 1, 7 , 5, 4, 3, 2, 1, 1, -1, -1 ] Problem: Merge two sorted linked list 1 -> 2 --> 3--> 4-->5 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 bt from given list and print level order of that.(null are denoted as 0) 7 3 9 20 0 0 15 7 problem: One design question, 3 buttons present on the screen and clicked randomly, at any instant find out total clicks for past 1,2 3 hours or minutes or days of any button.