Dropbox coding interview
questions, leaked.
25 problems reported across recent Dropbox interviews. Top patterns: array, hash table, string. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Dropbox's interview hits you with arrays and hash tables relentlessly. Out of 25 problems, 18 are array-based and 13 involve hash-table logic. The median difficulty is hard: 10 hard problems, 13 medium, only 2 easy. You're looking at design questions like Text Editor and Seat Reservation Manager, plus tricky string-and-hash patterns like Word Break II and Find Duplicate File in System. The assessment expects you to recognize when to layer multiple data structures together. If you freeze mid-OA on a hash-table collision or can't spot the union-find angle in a graph problem, StealthCoder runs invisibly and surfaces a working solution in seconds.
Top problems at Dropbox
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Simple Bank System | MEDIUM | 100.0 | 61% | Array · Hash Table · Design |
| 02 | Find Duplicate File in System | MEDIUM | 94.7 | 68% | Array · Hash Table · String |
| 03 | Game of Life | MEDIUM | 92.7 | 71% | Array · Matrix · Simulation |
| 04 | Web Crawler Multithreaded | MEDIUM | 92.7 | 50% | Depth-First Search · Breadth-First Search · Concurrency |
| 05 | Web Crawler | MEDIUM | 92.7 | 69% | String · Depth-First Search · Breadth-First Search |
| 06 | Seat Reservation Manager | MEDIUM | 90.4 | 66% | Design · Heap (Priority Queue) |
| 07 | Design a Text Editor | HARD | 90.4 | 47% | Linked List · String · Stack |
| 08 | Grid Illumination | HARD | 90.4 | 38% | Array · Hash Table |
| 09 | Letter Combinations of a Phone Number | MEDIUM | 90.4 | 64% | Hash Table · String · Backtracking |
| 10 | Word Break II | HARD | 90.4 | 54% | Array · Hash Table · String |
| 11 | Design Hit Counter | MEDIUM | 90.4 | 69% | Array · Binary Search · Design |
| 12 | Minimize Malware Spread II | HARD | 90.4 | 45% | Array · Hash Table · Depth-First Search |
| 13 | Word Pattern | EASY | 90.4 | 43% | Hash Table · String |
| 14 | Word Pattern II | MEDIUM | 90.4 | 49% | Hash Table · String · Backtracking |
| 15 | Median of Two Sorted Arrays | HARD | 90.4 | 44% | Array · Binary Search · Divide and Conquer |
| 16 | Number of Valid Words for Each Puzzle | HARD | 90.4 | 47% | Array · Hash Table · String |
| 17 | Two Sum | EASY | 90.4 | 56% | Array · Hash Table |
| 18 | Minimize Malware Spread | HARD | 90.4 | 42% | Array · Hash Table · Depth-First Search |
| 19 | Check If It Is a Good Array | HARD | 90.4 | 61% | Array · Math · Number Theory |
| 20 | Max Area of Island | MEDIUM | 87.9 | 73% | Array · Depth-First Search · Breadth-First Search |
| 21 | Guess the Word | HARD | 68.7 | 38% | Array · Math · String |
| 22 | Merge Intervals | MEDIUM | 61.9 | 49% | Array · Sorting |
| 23 | Top K Frequent Elements | MEDIUM | 61.9 | 65% | Array · Hash Table · Divide and Conquer |
| 24 | Number of Islands | MEDIUM | 52.4 | 62% | Array · Depth-First Search · Breadth-First Search |
| 25 | Number of Islands II | HARD | 52.4 | 40% | Array · Hash Table · Union Find |
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 Dropbox OA. The proctor cannot see it. Screen share cannot detect it. Made by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know.
Get StealthCoder- array18 · 72%
- hash table13 · 52%
- string9 · 36%
- depth first search6 · 24%
- breadth first search6 · 24%
- union find5 · 20%
- design4 · 16%
- simulation3 · 12%
- matrix3 · 12%
- backtracking3 · 12%
Arrays dominate the interview surface, but hash tables are the underlying glue. Nearly every hard problem pairs them together: Grid Illumination, Minimize Malware Spread II, Word Break II all need both. Strings appear in 9 problems and almost always interleave with hashing and backtracking. Depth-first search and breadth-first search are equally weighted at 6 each, typically in web-crawler and graph-connectivity variants. Union-find shows up less often (5 problems) but in high-stakes contexts like malware spread and island detection. The message is clear: nail array iteration, hash-map design patterns, and string manipulation first. Then spend time on DFS and BFS as fallback patterns. Design questions are frequent enough that you should understand the trade-offs between array heaps and balanced structures. If you hit an unfamiliar pattern or run out of time on a design problem during the live OA, StealthCoder is your safety net for invisible, real-time recovery.
Companies with similar patterns
If you prepped for Dropbox, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Dropbox.
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. Made by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Dropbox interview FAQ
How many array problems should I solve before the Dropbox interview?+
Array problems represent 18 of 25 reported questions. Drill all array fundamentals: rotation, partition, prefix sums, sliding window, two-pointer. Then focus on how arrays interact with hash tables in problems like Grid Illumination and Find Duplicate File in System. Skip edge cases on problems you've mastered; focus on the pattern coupling instead.
Is hash-table fluency enough, or do I need to know union-find?+
Hash tables appear in 13 problems, so yes, that's core. But union-find shows up in 5 problems, including Minimize Malware Spread II, which is hard-difficulty. You can pass without union-find if you're fast with DFS and BFS, but don't skip it entirely. Study it as a second priority, after arrays and hashes are solid.
What should I prioritize first for a Dropbox OA: strings or graphs?+
Strings (9 problems) come before graph work. Most string problems mix hash tables and backtracking, like Word Break II and Letter Combinations. Graphs (DFS/BFS, 6 problems each) are secondary. Get hash-table string patterns down, then move to traversal.
Are design questions common enough to study before Dropbox?+
Yes. Design appears in 4 top problems, including two hard problems: Text Editor and Seat Reservation Manager. You'll likely face at least one design question. Study the core patterns: when to use arrays vs linked lists, how to structure simulators, and when to introduce priority queues or stacks.
How hard is the median problem I'll face at Dropbox?+
The median is hard. Only 2 of 25 reported problems are easy. The remaining 13 medium and 10 hard problems expect you to combine multiple techniques. If you're strongest on medium-difficulty patterns, that's your baseline, but expect to encounter tricky layered problems like Median of Two Sorted Arrays and Grid Illumination.