Whatnot coding interview
questions, leaked.
7 problems reported across recent Whatnot interviews. Top patterns: array, string, matrix. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Whatnot's coding assessment hits you with seven problems across easy and medium difficulty, no hard problems in the dataset. Arrays dominate the question pool, showing up in five reported problems, with strings and matrices close behind. You're looking at a mix of classic patterns: two-pointers, depth-first search, sorting, and a few one-off topics like union-find and greedy. The assessment is front-loaded toward foundational data structures, which means you can build real momentum early if you drill the right order. If you hit a wall on the live OA, StealthCoder runs invisibly and surfaces a working solution in seconds, so you're never stuck on time.
Top problems at Whatnot
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Valid Palindrome II | EASY | 100.0 | 43% | Two Pointers · String · Greedy |
| 02 | Number of Islands | MEDIUM | 100.0 | 62% | Array · Depth-First Search · Breadth-First Search |
| 03 | Remove All Adjacent Duplicates In String | EASY | 87.8 | 72% | String · Stack |
| 04 | Group Anagrams | MEDIUM | 87.8 | 71% | Array · Hash Table · String |
| 05 | Search a 2D Matrix II | MEDIUM | 78.1 | 55% | Array · Binary Search · Divide and Conquer |
| 06 | Word Search | MEDIUM | 78.1 | 45% | Array · String · Backtracking |
| 07 | Squares of a Sorted Array | EASY | 78.1 | 73% | Array · Two Pointers · Sorting |
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 Whatnot 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- array5 · 71%
- string4 · 57%
- matrix3 · 43%
- two pointers2 · 29%
- depth first search2 · 29%
- sorting2 · 29%
- greedy1 · 14%
- stack1 · 14%
- breadth first search1 · 14%
- union find1 · 14%
The topic distribution is shallow and pattern-heavy. Array and string problems comprise the bulk of the reports, with matrix appearing in roughly a third of problems. You should spend 70 percent of your prep on array manipulation (especially with two-pointers and sorting), then block out focused time on string operations and grid-based DFS. The four medium problems are your actual filter. Valid Palindrome II and Squares of a Sorted Array teach two-pointers quickly, then level up to Number of Islands (DFS plus union-find hybrid) and Word Search (backtracking on a grid). If you're weak on matrix traversal or haven't locked down DFS, that's where StealthCoder earns its keep during the real assessment.
Companies with similar patterns
If you prepped for Whatnot, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Whatnot.
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.
Whatnot interview FAQ
How many array problems should I solve before the Whatnot assessment?+
Five of seven reported problems involve arrays. Solve at least 15 to 20 medium-tier array problems, focusing on two-pointers, sorting, and searching. Once those feel automatic, shift to string and matrix problems. Array fluency is non-negotiable for this interview.
What order should I drill topics for Whatnot?+
Start with two-pointers on arrays and strings (covers Valid Palindrome II and Squares of a Sorted Array). Then do hash-table and sorting (Group Anagrams). Last, spend three to four sessions on DFS and BFS for matrix/grid problems (Number of Islands, Word Search). Leave stack and union-find for review the night before.
Is the Whatnot assessment mostly easy or medium?+
Three easy, four medium, zero hard. The easy problems are gateways to speed and confidence. Don't camp on them. Hit Valid Palindrome II and Squares of a Sorted Array as warm-ups, then spend the bulk of your time on Group Anagrams, Word Search, and Number of Islands, which are the true difficulty filters.
Do I need to know union-find for Whatnot?+
Union-find appears in one reported problem (Number of Islands). It's a nice-to-have, not must-have. You can solve Number of Islands with DFS or BFS alone. Learn union-find if you have time, but prioritize two-pointers, arrays, and matrix DFS first.
Should I study backtracking before the Whatnot assessment?+
Yes. Word Search is a medium backtracking problem on a grid, and it's in the top problems. Spend one focused session on backtracking: understand the recursive pattern, how to mark visited cells, and when to prune branches. This topic directly appears in your assessment.