https://codeforces.com/contest/448/problem/C

exactly this problem was pasted in the interview document along with the examples and constraints, interiew felt cold and robotic and nothing much happened, could not solve in 45 mins(actual interview was for 45 mins, spent 40 mins tyring to figure out stuff and 5 mins for clsoing questions)..
Read a blog that says this is segment tree problem, not sure about the validity of the problem in a phone screen.

edit:
I wrestled during the interview, unfortunately could not bring the discussion and code to closure.

I say pasted because the line break was not present in the posted text,I had to manually indent and bring the lines down in order to read it on screen, examples were exactly the same, no changes...
Level L3
Location: Bengaluru, India