PayPal Interview Experience for Software Engineer-2 Chennai

Each round happens on a knock-out basis.

Round 1 : (Hackerearth based test) [Time : 1h15m]

This round had 2 questions. 

1. Given an array of size N and K queries, find the number of segments containing the index(from queires) which is leftmost or rightmost and the number at index is >= each elements of that segment Eg : arr[] = [1,2,3] K = [3] -> o/p : 3 ([3],[2,3][1,2,3])
2. Modification of this question(https://leetcode.com/problems/find-k-closest-elements/).

Verdict: cleared

Round 2 : F2F [Time : 1h]

1. Given an array and a target sum k, find all a[i] + a[j] = k. Follow up: handle if the array has both duplicate and non-duplicate elements
2. Find the first non-repeating character in the string (with only lowercase letters) https://leetcode.com/problems/first-unique-character-in-a-string/. Follow up : i ) contains both lowercase & uppercase ii) case-insensitive & case sensitive iii) in O(1) space complexity

Verdict: cleared

Round 3 : F2F [Time : 1h]

1. Find if a linked list is a palindrome [expected time & space complexity : O(n) & O(1)]. https://leetcode.com/problems/palindrome-linked-list/
2. Find the diameter of the binary tree(https://leetcode.com/problems/diameter-of-binary-tree/)
3. Validate if a tree is BST(https://leetcode.com/problems/validate-binary-search-tree/)

Verdict : rejected

Thoughts/Analysis: First logic/approach has to be explained and will be allowed to code only if the interviewer is satisfied. Most optimal solution on time and space complexity is required in the first cut. If u say a brute-force / sub-optimal solution, You will be asked to think of better solution and then only will be allowed to code. If you couldn’t come up with a solution in 20mins, the current question will be put on hold and next question will be asked. Thorough understanding of time & space complexity is a must. 

All The Best !!!