Problem database last updated: June 20, 2025
7 problems · 0 Easy, 5 Medium, 2 Hard · Ranked #192 of 458
0 Easy
0% · avg 23%
5 Medium
71% · avg 59%
2 Hard
29% · avg 18%
Based on 7 reported problems, Nextdoor interviews are significantly harder than average - 29% Hard vs 18% across all companies. The majority (71%) of questions are Medium difficulty, which is typical for companies that want to see solid fundamentals without excessive trick questions.
Compared to the industry average, Nextdoor puts unusual emphasis on design (28.6% of problems, 4.9x the industry average), two-pointers (28.6% of problems, 2.1x the industry average), hash-table (42.9% of problems, 1.9x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are string (42.9%), hash-table (42.9%), two-pointers (28.6%), design (28.6%). Problems below are sorted by frequency, the ones at the top are asked most often.
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
Compare Version Numbers Given two version strings, version1 and version2, compare them. A version string consists of revisions separated by dots '.'. The value of the revision is its i... | Medium | Very Likely | two-pointersstring | Solve |
All O`one Data Structure Design a data structure to store the strings' count with the ability to return the strings with minimum and maximum counts. | Hard | Very Likely | hash-tablelinked-listdesign | Solve |
Merge Intervals Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cove... | Medium | Very Likely | arraysorting | Solve |
Time Based Key-Value Store Design a time-based key-value data structure that can store multiple values for the same key at different time stamps and retrieve the key's value at a certain... | Medium | Likely | hash-tablestringbinary-search | Solve |
Divide Two Integers Given two integers dividend and divisor, divide two integers without using multiplication, division, and mod operator. | Medium | Likely | mathbit-manipulation | Solve |
Trapping Rain Water Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining. | Hard | Likely | arraytwo-pointersdynamic-programming | Solve |
Letter Combinations of a Phone Number Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any order. | Medium | Likely | hash-tablestringbacktracking | Solve |
Compare Version Numbers
SolveGiven two version strings, version1 and version2, compare them. A version string consists of revisions separated by dots '.'. The value of the revision is its i...
All O`one Data Structure
SolveDesign a data structure to store the strings' count with the ability to return the strings with minimum and maximum counts.
Merge Intervals
SolveGiven an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cove...
Time Based Key-Value Store
SolveDesign a time-based key-value data structure that can store multiple values for the same key at different time stamps and retrieve the key's value at a certain...
Divide Two Integers
SolveGiven two integers dividend and divisor, divide two integers without using multiplication, division, and mod operator.
Trapping Rain Water
SolveGiven n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.
Letter Combinations of a Phone Number
SolveGiven a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any order.
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Nextdoor interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Nextdoor interviews focus heavily on string, hash-table, two-pointers problems. If you're short on time, these are the categories to prioritize. The problems on this page are sorted by frequency, so start from the top and work your way down.
Beyond solving problems, practice explaining your approach. Nextdoor interviewers care about your thought process - how you break down a problem, consider edge cases, and evaluate tradeoffs between solutions. A clean O(n) solution you can explain clearly beats an O(log n) solution you can't articulate.
Looking for more companies? Browse all 458 companies in our directory, or sharpen your fundamentals with our free data structure visualizers and AI-powered DSA tutor.
Nextdoor has been reported to ask 7 distinct coding problems. The most common topics are string, hash-table, two-pointers. 0 are Easy difficulty, 5 are Medium, and 2 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 7 reported problems, Nextdoor interviews are significantly harder than average - 29% Hard vs 18% across all companies. 71% of questions are Medium difficulty. Focus on the high-frequency Medium problems first, then work through the Hard ones.
Start with the highest-frequency problems listed on this page. Focus on the core topics: string, hash-table, two-pointers. Practice solving them under time pressure and explaining your approach out loud. Mock interviews with AI can simulate the real experience.
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