Park Plus Backend Developer Interview Questions and Answers

The interviewer first asked me a puzzle and then asked me two DSA questions.
Puzzle: There are a large number of people sitting in a circular table with numbering as 1,2,3..
Given two numbers a and b, how to find out whether they are sitting opposite to each other or not.
DSA 1: Finding out the minimum capacity required to load the ship with all the weights given in an array in d days. (Binary Search approach)
DSA2: Given an array containing information about parents of a node in a tree, and q queries. Each query would contain the node number and a value n. You have to find the nth parent for the given node. You have to do this in such a way that the time complexity is less than linear and the memory usage is also minimal.
This was a tricky question where I was unable to give a logarithmic solution initially but with some hints from the interviewer, I was able to approach it.