System design interview question
"Design a real-time leaderboard for a game. Fifty million players, scores update constantly, and every player wants to see the global top 100 plus their own rank and the players immediately around them. 'What is my rank?' is the expensive question."
rank queries at scale, which is a specific and non-obvious problem. Showing a top-100 list is easy; telling player number 3,847,221 exactly where they stand among fifty million is not, because rank is a global aggregate that changes whenever anyone's score changes. The distinguishing content is why exact rank is expensive and what approximations are acceptable.
On Practick another engineer interviews you live for 60 minutes on a question from this bank. They have the full interviewer guide beside the call: the answers to your clarifying questions, the numbers to hand out, a ladder of follow-ups and a scoring rubric. You get the model solution once the session settles. It is free: interview someone for an hour and you have earned your own.
Book a free mock interviewAll 132 system design interview questions
System design mock interviews · DSA interview questions · Free mock interview practice · Browse interviewers · Sign in