HiLabs coding interview
questions, leaked.
3 problems reported across recent HiLabs interviews. Top patterns: string, dynamic programming, bit manipulation. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
HiLabs doesn't mess around. You're looking at three problems across their interview pipeline, and two of them are hard. String manipulation shows up twice, which means you're not just solving algorithms, you're parsing and transforming data under pressure. One easy problem (Water Bottles) gives you a confidence boost, but don't let it fool you into thinking the interview is straightforward. You need to be sharp on dynamic programming and bit manipulation before you go live. If you blank mid-assessment, StealthCoder runs invisible during screen share and surfaces a working solution in seconds, so you stay in control.
Top problems at HiLabs
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Maximize the Number of Partitions After Operations | HARD | 100.0 | 27% | String · Dynamic Programming · Bit Manipulation |
| 02 | Water Bottles | EASY | 67.9 | 71% | Math · Simulation |
| 03 | Parsing A Boolean Expression | HARD | 67.9 | 70% | String · Stack · Recursion |
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 HiLabs OA. The proctor cannot see it. Screen share cannot detect it. Built by an Amazon engineer who used it to pass JPMorgan's OA and system design loop.
Get StealthCoder- string2 · 67%
- dynamic programming1 · 33%
- bit manipulation1 · 33%
- bitmask1 · 33%
- math1 · 33%
- simulation1 · 33%
- stack1 · 33%
- recursion1 · 33%
The distribution is brutal in your favor if you prepare right. String problems anchor two of the three, so spending time on pattern recognition and state management there pays off immediately. Dynamic programming and bit manipulation each appear once, but they're paired with hard difficulty, meaning HiLabs values candidates who can think in states and masks under constraints. The easy problem (Water Bottles) is a simulation warmup, not your focus. Stack and recursion appear once each, both in the parsing problem, so understand recursive descent parsing and you've got that covered. Simulation is low frequency overall. Your hedge: if you hit a hard string-DP hybrid you haven't drilled, StealthCoder catches it live and you move forward without panic.
Companies with similar patterns
If you prepped for HiLabs, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass HiLabs.
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 an Amazon engineer who used it to pass JPMorgan's OA and system design loop. Works on HackerRank, CodeSignal, CoderPad, and Karat.
HiLabs interview FAQ
How many string problems should I solve before the HiLabs assessment?+
At least 10 to 15, focusing on substring partitioning, state transitions, and bitmask optimization. String appears in two of HiLabs' three known problems, so it's your highest-ROI study. Pair that with dynamic programming drills on similar constraints.
Should I study bit manipulation heavily for HiLabs?+
Yes, but contextually. Bit manipulation shows up in one hard problem alongside string and DP. Study it as a tool for state compression and optimization, not as isolated bitwise tricks. Understand bitmask DP patterns specifically.
Is the easy problem (Water Bottles) a real indicator of difficulty?+
No. One easy problem out of three doesn't change the curve. It's a false comfort. Expect the other two to be genuinely hard. Drill it as a confidence warm-up, then focus 80% of prep on hard string and recursion parsing problems.
What should I study first for HiLabs: DP or stack/recursion?+
Start with string fundamentals and DP together, since the hard partition problem likely combines both. Stack and recursion for parsing can follow after you're solid on DP state design. Simulation is lowest priority based on frequency.
How important is simulation for HiLabs prep?+
Low priority. Simulation appears once (Water Bottles, which is easy). Spend your prep time on the two hard problems: string partitioning with DP and boolean expression parsing with recursion. That's where the interview is decided.