SDE - Intern

There were three problems and 2 of them were medium and 1 was hard.
I was able to solve 1 medium comletely and got partial points of rest of two.
There problems are pretty good and never repeating.

I don't remember all the problems.

The Interview was scheduled in afternoon and inteviewer came and he elaborated what work he is doing in media.net and how long has been since he is working in media.net then i introduced my self.
After introductions interviewer said that he will give me one question and i have to explain him my best possible solution 
and after that i have to write code on google docs sheet.
Then interviewer explained the problem to me and also he explained few test cases.

This round was an open ended problem discussion round and this was by far by worst interview.
The round was so bad that at a point in interview i was thinking of leaving the interview.
So Interview started with the Introduction of interviewer.
The interviewer was having 7 years of work experience in media.net.
After his introduction i introduced myself to him and he asked few follow up questions based on my resume projects and tech stack.
Then he asked me an open ended question :
I was given a lattitue and longitude of a place and i had to design algorithm for trending feed generation for twitter for that Area and there will be a weight associated with each twitter post which will represent trending score of that post , higher treding score means better post.
I had never faced system design or open ended problem before this interview so my brain just freezed and i was not able to give his even brute force solution and after some time he started talking about scale and all and i was just sitting blank for starting 15-20 minutes.
So i got few learnings from this round that everyone should have basic idea of system design and scale estimations before appearing for interviews of good companies , that will for sure will be a good weapon to drive your interview in a positive direction.