One phone call with HackerRank included LeetCode easy-medium exercises. After that, there were two rounds of coding interviews with two SDEs each. This time, the exercises were medium-hard. Sadly, from the total of four problems, I was able to solve two. The ones I did not solve were really easy but caught me off guard.

Practice because they want the most optimal solution and have some good questions ready. I had a lot of fun though, and I learned a lot.

Questions from the second round (that I can remember):

1. Build a tree using two arrays: one containing the tree in traversal order and another array for the inorder traversal.

2. From a 2D maze, find the number of unique paths.

3. Given an array whose numbers start increasing and then decrease after an inflexion point, find a target number.