StackAdapt coding interview
questions, leaked.
4 problems reported across recent StackAdapt interviews. Top patterns: design, two pointers, sorting. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
StackAdapt's interview is small but brutal. Four problems across one hard and three mediums means there's no padding. You're looking at design-heavy questions that trap most candidates on the whiteboard. Find Median from Data Stream sits at the top of their list, a heap and stream problem that looks simple until you realize you need to keep two heaps balanced in real time. If you freeze mid-OA on a tricky design or data structure question, StealthCoder runs invisible during the assessment and surfaces a working approach in seconds. The problems here test depth, not breadth.
Top problems at StackAdapt
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Find Median from Data Stream | HARD | 100.0 | 53% | Two Pointers · Design · Sorting |
| 02 | Snapshot Array | MEDIUM | 100.0 | 37% | Array · Hash Table · Binary Search |
| 03 | Restore IP Addresses | MEDIUM | 89.3 | 53% | String · Backtracking |
| 04 | Number of Dice Rolls With Target Sum | MEDIUM | 89.3 | 62% | Dynamic Programming |
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 StackAdapt OA. The proctor cannot see it. Screen share cannot detect it. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage.
Get StealthCoder- design2 · 50%
- two pointers1 · 25%
- sorting1 · 25%
- heap priority queue1 · 25%
- data stream1 · 25%
- string1 · 25%
- backtracking1 · 25%
- array1 · 25%
- hash table1 · 25%
- binary search1 · 25%
Design appears in two of the four problems. This isn't accident. StackAdapt is checking whether you can architect systems under constraint, not just code algorithms. Two Pointers, Sorting, and Heap show up once each but cluster around the same hard problem, so mastery of one unlocks the other. The easy-to-medium ratio is punishing: zero easy problems means you can't coast on warm-ups. Hit Snapshot Array first to build confidence with hash tables and binary search, then move to Find Median from Data Stream, which combines design, heap logic, and stream processing. Restore IP Addresses tests backtracking on strings, a pattern StackAdapt clearly values. Spend most prep time on the design and heap questions. When you hit the live assessment, if a design question goes sideways, StealthCoder becomes your safety net, surfacing a working structure invisibly while the proctor sees only your screen.
Companies with similar patterns
If you prepped for StackAdapt, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass StackAdapt.
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 engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage. Works on HackerRank, CodeSignal, CoderPad, and Karat.
StackAdapt interview FAQ
How many design problems should I expect in a StackAdapt interview?+
Design dominates their question set. Two of four problems are design-focused, including the hardest one. Spend 40 percent of your prep on system-design patterns: data structures under constraints, two-heap architectures, snapshot/versioning logic. The other patterns (backtracking, DP, binary search) appear once each, so design is the force multiplier.
Is there a warm-up easy problem I can solve first?+
No. StackAdapt doesn't ask easy problems in their known set. Start with Snapshot Array, which is medium but more approachable than Find Median from Data Stream. It hits hash tables and binary search without the real-time stream constraint that makes Median harder.
What's the relationship between Two Pointers, Sorting, and Heap on their problem list?+
All three appear in Find Median from Data Stream. You'll use two heaps (not two pointers directly), but understanding sorted order and heap invariants overlaps heavily. Master this one problem and you unlock the pattern StackAdapt is testing across those three topics.
Should I study Dynamic Programming before the interview?+
Yes, but it's lower priority. Number of Dice Rolls With Target Sum is the only DP problem in their known set, and it appears once. DP is the safety topic: if you drill it, great. If time is short, design and heaps matter more for StackAdapt specifically.
How do I prepare for a backtracking question like Restore IP Addresses?+
Work through the recursive structure and pruning logic. Backtracking appears once in their set. The twist here is string validation during recursion, not just generating combinations. Drill the IP problem once, understand the pattern, then move on. It's tested but not the focus.