Interactive interview questions
10 interactive problems tagged across recent interview reports. Drilled most heavily by google, linkedin, and dropbox.
Interactive problems ask you to solve a puzzle using only a hidden API or opaque interface. You don't see the full input upfront. Instead, you query the system, get responses, and adapt your strategy in real time. Google and LinkedIn ask these constantly across OAs and on-sites. With 10 core variants in circulation and no way to brute-force a memorized solution during your assessment, Interactive problems are where prep gaps become visible fast. StealthCoder reads the problem statement and API contract, then generates the right query sequence and control flow in seconds, invisible to the proctor.
Most-asked interactive problems
| # | Problem | Diff | # Companies | Pass % |
|---|---|---|---|---|
| 01 | Find the Celebrity | MEDIUM | 7 | 48% |
| 02 | Robot Room Cleaner | HARD | 6 | 78% |
| 03 | Guess the Word | HARD | 5 | 38% |
| 04 | Leftmost Column with at Least a One | MEDIUM | 2 | 55% |
| 05 | Read N Characters Given read4 II - Call Multiple Times | HARD | 2 | 43% |
| 06 | Web Crawler | MEDIUM | 2 | 69% |
| 07 | Find in Mountain Array | HARD | 1 | 40% |
| 08 | Guess Number Higher or Lower | EASY | 1 | 56% |
| 09 | Read N Characters Given Read4 | EASY | 1 | 42% |
| 10 | Shortest Path in a Hidden Grid | MEDIUM | 1 | 44% |
You can't drill every interactive variant before the assessment. StealthCoder runs invisibly during screen share and solves whichever variant they throw at you. No browser extension. No detection signature. Made by a working Amazon engineer who got tired of watching qualified friends bomb OAs they'd solve cold in an IDE.
Get StealthCoderThe pattern reveals itself in the problem statement: phrases like 'you may only call', 'limited API calls', 'hidden array', 'don't have direct access', or 'use the provided interface'. Common subtypes include binary search on hidden arrays (find-in-mountain-array, guess-number-higher-or-lower), matrix traversal with hidden cells (leftmost-column-with-at-least-a-one, robot-room-cleaner), I/O simulation (read-n-characters-given-read4), and graph exploration (web-crawler, shortest-path-in-a-hidden-grid). The trap is treating it like a normal algorithm problem; the skill is designing an optimal query plan with minimal calls. Drill in order: binary search variants first, then matrix/grid probing, then I/O buffering. When an Interactive variant lands in your live OA and the API docs feel unfamiliar, StealthCoder is your safety net.
Companies that hire most on interactive
10 interactive problems.
You won't drill them all. Pass anyway.
Interactive is one of the patterns interviews actually filter on. Memorizing every variant in a week is a fantasy. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds, no matter which interactive flavor lands in your live OA. Made by a working Amazon engineer who got tired of watching qualified friends bomb OAs they'd solve cold in an IDE. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Interactive interview FAQ
How many Interactive problems should I drill before an OA?+
All 10 core patterns if possible. They don't overlap much. Google and LinkedIn together ask 13 versions across different teams, so breadth matters more than depth. Focus on understanding the API contract first, then optimize call count.
Is Interactive the hardest pattern for Google or LinkedIn?+
Not the hardest, but unavoidable. Google has 7 live variants, LinkedIn 6. They're not as common as arrays or trees, but they're heavily weighted in final rounds because they test real systems thinking, not just algorithm knowledge.
How do I recognize an Interactive problem in the wild?+
Look for 'call the API', 'function you can invoke', 'don't read the full input', 'limited calls allowed', or a custom class/interface in the problem statement. If you're not given the full array or grid upfront, it's likely Interactive.
Which company drills Interactive problems the hardest?+
Google, with 7 tagged problems across product and infrastructure teams. LinkedIn follows with 6. Dropbox, HubSpot, and Lyft each have 4 to 5. It's a strong signal for companies building search, discovery, and crawling systems.
What's the biggest mistake candidates make on Interactive problems?+
Assuming the full data is available and coding a naive solution, then running into call limits or timeouts. Read the API contract twice. Plan your query strategy on paper. Test your call count before submitting.