iOS interview questions reported at Uber
11 questions candidates reported being asked at Uber. Anonymous and unverified, so treat it as a hint of what to expect.
They cover System design & staff+, Coding rounds. Every question below links to a full answer with the common traps and the follow-ups an interviewer is likely to ask, so you can practise the way the interview goes: answer first, then defend it.
- Design an API rate limiter, then say how an iOS client should behave under one. Compare token bucket with a fixed window.
- Design the client of a Tinder-style swipe app: card prefetching, instant feel, and swipes that must not be lost or duplicated on a bad network.
- Design the rider app of a ride-hailing service: requesting, matching, a live driver on the map, trip states and a bad network.
- Design the API behind a photo feed: pagination, response shape, image variants, caching and what the client needs from it.
- Implement a hash map from scratch (get, set, remove), then extend it: what do you test and how does resizing work?
- Given a binary search tree and a decimal target, find the value closest to the target. Why can you stop descending one side?
- Return the values you see when looking at a binary tree from its right side. How does a level-order walk give it, and what is the trap with a left-only branch?
- Print the boundary of an N-ary tree counterclockwise: root, left edge, leaves left to right, right edge going up. How do you avoid printing a node twice?
- Given function entry and exit events with timestamps, print the time spent in each function when it exits. How do you separate total time from self time, and handle recursion?
- You get 60 to 90 minutes to build a small app live (a photo search, a movie list from JSON, a recipe app, a list with counters). How do you spend the time and what do interviewers look for?
- In a live round you are given existing code to review and then asked to add a feature to it. How do you review it quickly and what do you fix first?