Each round happens on knock-out basis.
Round 1 : (Hackerearth based test) [Time : 1h15m]
This round had 2 questions.
Result : Cleared
Round 2 : F2F [Time : 1h]
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)
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 if a sorted string is given]
Result : Cleared
Round 3 : F2F [Time : 1h]
find if a linked list is a palindrome [expected time & space complexity : O(n) & O(1)]
https://leetcode.com/problems/palindrome-linked-list/
find the diameter of the binary tree
https://leetcode.com/problems/diameter-of-binary-tree/
validate if a tree is BST
https://leetcode.com/problems/validate-binary-search-tree/
Result : 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, u will be asked to think of better solution and then only will be allowed to code. If u couldn't come up with a solution in 20mins, 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 !!!