Sentry coding interview
questions, leaked.
2 problems reported across recent Sentry interviews. Top patterns: array, string, simulation. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Sentry's coding interview is tight. Two problems total, split one medium and one hard, means every minute counts and there's no room for a restart. The medium problem, Design Hit Counter, pulls from streams and binary search. The hard problem, Text Justification, is pure simulation on arrays and strings. You'll hit array patterns in both, so that's your warmup. If you've done system-design interviews before, the counter problem will feel familiar, but the justification problem is a syntax grind that catches people off guard mid-OA. StealthCoder runs invisibly during the live assessment, so if the simulation logic breaks down on Text Justification, you've got a safety net that surfaces working code in seconds.
Top problems at Sentry
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Text Justification | HARD | 100.0 | 48% | Array · String · Simulation |
| 02 | Design Hit Counter | MEDIUM | 79.8 | 69% | Array · Binary Search · Design |
Frequencies derived from public community-tagged interview reports. Click a row to view on LeetCode.
You have a week, maybe less. You can't out-grind the list above. StealthCoder runs invisibly during the actual Sentry OA. The proctor cannot see it. Screen share cannot detect it. Built by a senior engineer who knows the OA is theater. This is the script.
Get StealthCoder- array2 · 100%
- string1 · 50%
- simulation1 · 50%
- binary search1 · 50%
- design1 · 50%
- queue1 · 50%
- data stream1 · 50%
Array work is the baseline here: both problems touch it. String manipulation and simulation logic dominate the hard problem, so that's where your prep time should go first. The medium problem layers in binary search and design thinking, which suggests Sentry wants to see how you handle time-indexed queries and state management, not just raw coding speed. Topic distribution is wide but shallow, so you're not facing deep algorithmic trees. The hard problem is the bottleneck. Text Justification requires careful index tracking and string building, and it's easy to get formatting wrong under pressure. That's where StealthCoder becomes your hedge: if you blank on the exact spacing rules at minute 45, the solution appears and you move on without the proctor seeing a thing.
Companies with similar patterns
If you prepped for Sentry, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Sentry.
Memorizing every problem above in a week is a fantasy. StealthCoder is the hedge: an AI overlay that's invisible during screen share. It reads the problem on screen and surfaces a working solution in under 2 seconds. Built by a senior engineer who knows the OA is theater. This is the script. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Sentry interview FAQ
Should I practice both problems or skip one?+
Practice both. Sentry gives you two, and they're different enough that drilling only one leaves you vulnerable. Text Justification is the harder wall, so put 60% of your time there. Design Hit Counter is faster to solve once you see the pattern, so it's your confidence builder.
Is array knowledge enough for Sentry's assessment?+
Array is foundational and shows up in both problems, but it's not enough alone. You also need to handle string formatting (Text Justification) and querying time-indexed data (Design Hit Counter). Array is your entry point, not your exit.
How much time should I spend on simulation and binary search?+
Simulation is critical for the hard problem and takes the most prep time. Binary search appears in the medium problem but as a supporting tool, not the main logic. Spend 70% of binary-search time understanding when to apply it, 30% on implementation.
What happens if I finish the medium problem early?+
Don't celebrate yet. Text Justification is the real test. Use the extra time to re-read the justification problem statement line by line, check the examples for edge cases (single word per line, different length strings, uneven distributions), and sketch your solution before coding.
Is design thinking important for this interview?+
Yes, for Design Hit Counter. The problem asks you to architect a time-aware counter, so they want to see how you structure state and handle lookups. It's not a full system-design interview, but explaining your approach during walkthrough matters.