Microsoft Software Engineer II interview questions

Got a call from the recruiter, who setup a phone screen with one of the members of the hiring team. That process took about a week After clearing the tech screen I was invited onsite for a round of interviews , the entire process took about 2 weeks Round 1 - Dynamic programming and the interviewer doesn't acknowledge the concept of using an array of 256 characters and wants me to throw in the phrase "we will use a Hashmap". A question which if solved genuinely takes a few hours and cannot be finished and tested in 40 mins unless we are copying it from leetcode Round 2 - Design the game of boggle and return a list of all the words that are of length 3 or more, i gave the recursive solution by the end but the interviewer is looking for a better solution ( recursive but less lines of code), a question which cannot be coded and tested in 40 mins Round 3 - What is a binary search tree ? why do we use them ? Write code to check if a given binary tree is a binary search tree ( gave the solution using in-order traversal but the interviewer thinks that the code is hard to read and isn't maintainable and writes a line of code using the Enumerable class of C# He then goes on for 30 minutes on a NP complete problem and did not have a clear idea of what he was asking, " we use constraints" and "these are problems open discussions" were the 2 phrases iterated throughout A negative experience