Nextdoor coding interview
questions, leaked.
8 problems reported across recent Nextdoor interviews. Top patterns: hash table, string, design. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Nextdoor's interview is six medium-difficulty problems and two hard ones. No easy warm-ups. You're walking into a hash-table and string gauntlet: three problems each, plus design challenges like All O`one Data Structure and Time Based Key-Value Store that require both data-structure fluency and systems thinking. The bar is mid-level consistent, not beginner-friendly. If you blank on a hash-table problem during the live assessment, StealthCoder surfaces a working solution in seconds, invisible to the proctor. That hedge matters here.
Top problems at Nextdoor
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Compare Version Numbers | MEDIUM | 100.0 | 42% | Two Pointers · String |
| 02 | All O`one Data Structure | HARD | 98.0 | 44% | Hash Table · Linked List · Design |
| 03 | Merge Intervals | MEDIUM | 78.9 | 49% | Array · Sorting |
| 04 | Letter Combinations of a Phone Number | MEDIUM | 64.4 | 64% | Hash Table · String · Backtracking |
| 05 | Trapping Rain Water | HARD | 64.4 | 65% | Array · Two Pointers · Dynamic Programming |
| 06 | Nested List Weight Sum | MEDIUM | 64.4 | 86% | Depth-First Search · Breadth-First Search |
| 07 | Divide Two Integers | MEDIUM | 64.4 | 18% | Math · Bit Manipulation |
| 08 | Time Based Key-Value Store | MEDIUM | 64.4 | 49% | Hash Table · String · Binary Search |
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 Nextdoor 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- hash table3 · 38%
- string3 · 38%
- design2 · 25%
- two pointers2 · 25%
- array2 · 25%
- linked list1 · 13%
- doubly linked list1 · 13%
- sorting1 · 13%
- backtracking1 · 13%
- dynamic programming1 · 13%
Hash-tables and strings dominate the problem set, appearing in roughly half the questions you'll see. Two-pointers and arrays follow as secondary patterns. What's notable: Nextdoor pairs basic topics with design requirements. Compare Version Numbers looks simple until you realize the two-pointer string parsing. Time Based Key-Value Store and All O`one Data Structure demand that you own both the data structure logic and the implementation under pressure. Start with the hash-table and string problems first, then shift to two-pointers for string manipulation. The two hard problems (All O`one and Trapping Rain Water) are pattern-heavy; if you haven't drilled monotonic stacks or doubly-linked lists at interview speed, StealthCoder is your live safety net.
Companies with similar patterns
If you prepped for Nextdoor, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Nextdoor.
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.
Nextdoor interview FAQ
How many hash-table problems should I solve before the Nextdoor interview?+
Hash-table shows up in three of eight problems reported. Solve at least 10-15 hash-table problems on your own to feel solid, then drill design-flavored ones like Time Based Key-Value Store and All O`one. That's where the difficulty spike lives.
Is string manipulation enough, or do I need two-pointers?+
Both. Two-pointers appears in two problems here, including Compare Version Numbers, which pairs string parsing with pointer logic. Drill them together, not separately. Practice splitting and comparing strings with pointers to avoid off-by-one errors under pressure.
Should I study design patterns before data structures?+
No. Nextdoor's design problems (All O`one, Time Based Key-Value Store) are design-wrapped data structures, not systems design. Master hash-tables, linked lists, and binary search first. Then layer design thinking on top.
What's the hardest pattern I should expect?+
Trapping Rain Water and All O`one Data Structure. The first uses monotonic stacks and dynamic programming on arrays; the second requires a custom doubly-linked list with O(1) operations. Both are hard problems. If you haven't built a doubly-linked list from scratch, drill that specifically.
How much time should I spend on backtracking?+
Backtracking appears once, in Letter Combinations of a Phone Number. It's a medium problem and a classic. Solve it once cleanly, understand the recursion tree, then move on. Hash-table and string problems will give you better ROI before the interview.