Reddit coding interview
questions, leaked.
6 problems reported across recent Reddit interviews. Top patterns: hash table, design, data stream. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Reddit's coding interviews hit you with design and hash-table problems back-to-back. Six problems reported across their loop, but don't let the small sample fool you: half are medium or hard, and they're obsessed with systems-level thinking. LRU Cache, Logger Rate Limiter, Design Hit Counter. These aren't leetcode toys. They want to see if you can architect under pressure. If you freeze on a design problem mid-assessment, StealthCoder runs invisibly and surfaces a working solution in seconds.
Top problems at Reddit
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Word Ladder | HARD | 100.0 | 43% | Hash Table · String · Breadth-First Search |
| 02 | Number of Ways to Buy Pens and Pencils | MEDIUM | 88.6 | 56% | Math · Enumeration |
| 03 | LRU Cache | MEDIUM | 81.6 | 45% | Hash Table · Linked List · Design |
| 04 | Logger Rate Limiter | EASY | 70.7 | 77% | Hash Table · Design · Data Stream |
| 05 | Design Hit Counter | MEDIUM | 70.7 | 69% | Array · Binary Search · Design |
| 06 | Number of Islands | MEDIUM | 57.2 | 62% | Array · Depth-First Search · Breadth-First 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 Reddit OA. The proctor cannot see it. Screen share cannot detect it. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too.
Get StealthCoder- hash table3 · 50%
- design3 · 50%
- data stream2 · 33%
- breadth first search2 · 33%
- array2 · 33%
- string1 · 17%
- linked list1 · 17%
- doubly linked list1 · 17%
- binary search1 · 17%
- queue1 · 17%
Hash tables and design dominate the pattern here. Three hash-table problems, three design problems, and heavy overlap between them. Start with LRU Cache and Logger Rate Limiter to build muscle memory on cache patterns and timestamp-based state. Data-stream problems (Hit Counter, Logger Rate Limiter) appear twice, so get comfortable queuing and windowing data. BFS and DFS each show up once, tied to graph traversal on Word Ladder and Number of Islands. The hard problem is Word Ladder, a BFS classic disguised as a string puzzle. You'll see one easy (Logger Rate Limiter), four medium, and one hard. Most candidates nail the easy, choke on design. That's where StealthCoder is your hedge if you blank on the structure mid-OA.
Companies with similar patterns
If you prepped for Reddit, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Reddit.
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 an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Reddit interview FAQ
Should I drill LRU Cache before Design Hit Counter?+
Yes. LRU Cache teaches the doubly-linked-list and hash-table combo that Hit Counter builds on. Both are design problems, but LRU is the foundation. You'll see cache patterns across Reddit's loop.
How much time should I spend on Word Ladder?+
Word Ladder is the only hard problem reported. It's a BFS graph traversal disguised as a string problem. Practice it once, understand the adjacency logic, then move on. One hard doesn't dominate the interview.
Do I need to memorize design patterns for Reddit?+
Not memorize. Internalize structure. Three of six problems are design. Focus on LRU Cache and Logger Rate Limiter first. Both teach you how to track state, invalidate entries, and reason about tradeoffs under time pressure.
Is binary search important for Reddit interviews?+
It appears once, in Design Hit Counter. It's not a primary focus, but know how to apply it to time-windowed data. It's the dull end of the dataset here.
How many hash-table problems should I solve before the interview?+
Hash tables appear in half the reported problems. Solve all three: LRU Cache, Logger Rate Limiter, and Word Ladder. You need speed and pattern recognition. Three problems is enough to build confidence.