Activision coding interview
questions, leaked.
3 problems reported across recent Activision interviews. Top patterns: string, array, hash table. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Activision's assessment is small but deceptive. Three problems across easy and medium, but they're testing pattern recognition hard. You'll see string manipulation twice, array work once, and two of the three problems chain multiple data structures together. The assessment hits recursion, hashing, and stack mechanics. Most candidates come in expecting a straightforward medium grind and choke on the back-to-back complexity. StealthCoder is the safety net if you blank mid-assessment and need a working solution in seconds while the proctor sees nothing.
Top problems at Activision
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Reformat Phone Number | EASY | 100.0 | 67% | String |
| 02 | Number of Divisible Triplet Sums | MEDIUM | 65.9 | 68% | Array · Hash Table |
| 03 | Decode String | MEDIUM | 65.9 | 61% | 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 Activision OA. The proctor cannot see it. Screen share cannot detect it. Built by an engineer at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share.
Get StealthCoder- string2 · 67%
- array1 · 33%
- hash table1 · 33%
- stack1 · 33%
- recursion1 · 33%
The topic distribution is heavily weighted toward strings (appearing in two of three problems), which is your lead. But neither string problem is pure manipulation. Reformat Phone Number is deceptive easy; it's checking your attention to parsing rules. Decode String and Number of Divisible Triplet Sums are the real pressure. Decode String forces you to juggle stack, recursion, and string parsing simultaneously. The triplet problem requires hash-table thinking under array constraints. Start with string fundamentals, then lock in stack-based recursion patterns before your OA. If you hit the triplet or decode problem live and freeze, StealthCoder surfaces a working approach invisibly while you're screen-sharing.
Companies with similar patterns
If you prepped for Activision, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Activision.
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 at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Activision interview FAQ
Should I spend more time on strings or arrays for Activision's assessment?+
Strings. Two of the three reported problems center on string work, and both involve parsing or encoding rules. Master string iteration, character classification, and building/rebuilding strings under constraints. Arrays matter but appear only in the triplet sum problem, which also pulls in hashing.
Is recursion really that important for Activision's OA?+
Yes. The Decode String problem explicitly demands it. The pattern is: recursion backs up your stack unwinding logic. You don't need to be a recursion wizard, but you must trace nested structures and know when to recurse versus iterate. Practice one hard nested-parsing problem before the OA.
How much time should I allocate to hash-table patterns?+
One of three problems uses hashing directly (the triplet sum). It's not the majority, but it's non-negotiable. Spend 3 to 4 focused sessions on hash-table frequency counting and lookups. You won't need advanced variants, just solid fundamentals.
Is the easy problem worth practicing, or should I skip to mediums?+
Don't skip it. Reformat Phone Number tests reading comprehension and careful implementation. Activision candidates often rush it and introduce off-by-one bugs or formatting errors. Solve it cold once to calibrate your parsing habits before the harder two.
What's the biggest gotcha in these three problems?+
Chaining patterns. Decode String isn't just recursion; it's recursion plus stack plus string building. The triplet problem isn't just arrays; it's arrays plus hashing plus constraint tracking. Each problem stacks two or three techniques. Drill them combined, not in isolation.