eBay coding interview
questions, leaked.
78 problems reported across recent eBay interviews. Top patterns: array, string, hash table. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
eBay's assessment hits you with 78 problems across a brutal 63% medium/hard split. Arrays dominate the list (42 problems), followed by strings (24) and hash tables (20). You're looking at a high bar: LRU Cache, Partition Equal Subset Sum, and Minimum Window Subsequence are the kinds of problems that separate offers from rejections. If you blank on a sliding-window or DP pattern mid-OA, StealthCoder runs invisibly during the assessment and surfaces a working solution in seconds. That's your hedge for the gaps in your prep.
Top problems at eBay
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Partition Equal Subset Sum | MEDIUM | 100.0 | 48% | Array · Dynamic Programming |
| 02 | LRU Cache | MEDIUM | 97.7 | 45% | Hash Table · Linked List · Design |
| 03 | Binary Gap | EASY | 95.1 | 65% | Bit Manipulation |
| 04 | Alternating Digit Sum | EASY | 95.1 | 68% | Math |
| 05 | Subtree of Another Tree | EASY | 95.1 | 50% | Tree · Depth-First Search · String Matching |
| 06 | Design Skiplist | HARD | 95.1 | 58% | Linked List · Design |
| 07 | Minimum Window Subsequence | HARD | 95.1 | 44% | String · Dynamic Programming · Sliding Window |
| 08 | Remove One Element to Make the Array Strictly Increasing | EASY | 95.1 | 29% | Array |
| 09 | Minimize Maximum Pair Sum in Array | MEDIUM | 95.1 | 81% | Array · Two Pointers · Greedy |
| 10 | Number of Islands | MEDIUM | 89.2 | 62% | Array · Depth-First Search · Breadth-First Search |
| 11 | Word Ladder | HARD | 81.5 | 43% | Hash Table · String · Breadth-First Search |
| 12 | Open the Lock | MEDIUM | 76.7 | 61% | Array · Hash Table · String |
| 13 | Spiral Matrix | MEDIUM | 76.7 | 54% | Array · Matrix · Simulation |
| 14 | Group Anagrams | MEDIUM | 76.7 | 71% | Array · Hash Table · String |
| 15 | Move Zeroes | EASY | 76.7 | 63% | Array · Two Pointers |
| 16 | Set Matrix Zeroes | MEDIUM | 70.8 | 61% | Array · Hash Table · Matrix |
| 17 | Reconstruct Itinerary | HARD | 70.8 | 44% | Depth-First Search · Graph · Eulerian Circuit |
| 18 | Meeting Rooms II | MEDIUM | 70.8 | 52% | Array · Two Pointers · Greedy |
| 19 | Word Search II | HARD | 70.8 | 37% | Array · String · Backtracking |
| 20 | Valid Parentheses | EASY | 70.8 | 42% | String · Stack |
| 21 | Binary Tree Zigzag Level Order Traversal | MEDIUM | 70.8 | 62% | Tree · Breadth-First Search · Binary Tree |
| 22 | Course Schedule | MEDIUM | 70.8 | 49% | Depth-First Search · Breadth-First Search · Graph |
| 23 | Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit | MEDIUM | 70.8 | 57% | Array · Queue · Sliding Window |
| 24 | Kth Largest Element in an Array | MEDIUM | 70.8 | 68% | Array · Divide and Conquer · Sorting |
| 25 | Course Schedule II | MEDIUM | 70.8 | 53% | Depth-First Search · Breadth-First Search · Graph |
| 26 | Pow(x, n) | MEDIUM | 63.2 | 37% | Math · Recursion |
| 27 | Rotting Oranges | MEDIUM | 63.2 | 57% | Array · Breadth-First Search · Matrix |
| 28 | Generate Parentheses | MEDIUM | 63.2 | 77% | String · Dynamic Programming · Backtracking |
| 29 | Best Time to Buy and Sell Stock II | MEDIUM | 63.2 | 70% | Array · Dynamic Programming · Greedy |
| 30 | Search in Rotated Sorted Array | MEDIUM | 63.2 | 43% | Array · Binary Search |
| 31 | Longest ZigZag Path in a Binary Tree | MEDIUM | 63.2 | 67% | Dynamic Programming · Tree · Depth-First Search |
| 32 | Binary Search Tree to Greater Sum Tree | MEDIUM | 63.2 | 88% | Tree · Depth-First Search · Binary Search Tree |
| 33 | Decode String | MEDIUM | 63.2 | 61% | String · Stack · Recursion |
| 34 | Concatenated Words | HARD | 63.2 | 49% | Array · String · Dynamic Programming |
| 35 | Longest Substring Without Repeating Characters | MEDIUM | 63.2 | 37% | Hash Table · String · Sliding Window |
| 36 | Two Sum | EASY | 63.2 | 56% | Array · Hash Table |
| 37 | Design a Stack With Increment Operation | MEDIUM | 63.2 | 80% | Array · Stack · Design |
| 38 | Time Based Key-Value Store | MEDIUM | 52.5 | 49% | Hash Table · String · Binary Search |
| 39 | Matchsticks to Square | MEDIUM | 52.5 | 41% | Array · Dynamic Programming · Backtracking |
| 40 | Longest Valid Parentheses | HARD | 52.5 | 36% | String · Dynamic Programming · Stack |
| 41 | Rank Teams by Votes | MEDIUM | 52.5 | 59% | Array · Hash Table · String |
| 42 | Reorganize String | MEDIUM | 52.5 | 56% | Hash Table · String · Greedy |
| 43 | Top K Frequent Elements | MEDIUM | 52.5 | 65% | Array · Hash Table · Divide and Conquer |
| 44 | Find Pivot Index | EASY | 52.5 | 61% | Array · Prefix Sum |
| 45 | Valid Palindrome II | EASY | 52.5 | 43% | Two Pointers · String · Greedy |
| 46 | Integer to English Words | HARD | 52.5 | 34% | Math · String · Recursion |
| 47 | Permutations | MEDIUM | 52.5 | 81% | Array · Backtracking |
| 48 | Koko Eating Bananas | MEDIUM | 52.5 | 49% | Array · Binary Search |
| 49 | Nested List Weight Sum | MEDIUM | 52.5 | 86% | Depth-First Search · Breadth-First Search |
| 50 | Roman to Integer | EASY | 52.5 | 65% | Hash Table · Math · String |
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 eBay OA. The proctor cannot see it. Screen share cannot detect it. Made for the engineer who has done the work but might still blank with a webcam pointed at him.
Get StealthCoder- array42 · 54%
- string24 · 31%
- hash table20 · 26%
- dynamic programming15 · 19%
- depth first search12 · 15%
- sorting12 · 15%
- breadth first search10 · 13%
- binary search8 · 10%
- matrix8 · 10%
- two pointers8 · 10%
Arrays are the foundation here; nearly 54% of the reported problems touch array manipulation. String problems (24 reports) are a close second, and hash tables (20) unlock solutions for caching and group operations like anagrams. Dynamic programming appears in 15 problems but punches above its weight: Partition Equal Subset Sum and Minimum Window Subsequence are both medium-to-hard DP patterns you can't wing. Graph traversal (DFS and BFS combined, 22 problems) matters for island-counting and lock-opening style problems. Sorting and two-pointers (12 and 8 respectively) are sneaky prerequisites for greedy and array-manipulation questions. Hit arrays and strings first; they're your volume. Then nail DP and hash tables before test day, because that's where candidates typically wall out. When you hit the live OA, StealthCoder is your real-time backup if an unfamiliar pattern lands.
Companies with similar patterns
If you prepped for eBay, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass eBay.
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 for the engineer who has done the work but might still blank with a webcam pointed at him. Works on HackerRank, CodeSignal, CoderPad, and Karat.
eBay interview FAQ
How many array problems should I solve before eBay's OA?+
Arrays show up in 42 of the 78 reported problems. Drill at least 20 to 25 distinct array patterns (two-pointers, sliding window, rotation, partition, etc.). You'll see at least 2 to 3 array problems in your actual OA. Skipping array prep is a fast way to bomb early.
Is dynamic programming required for eBay?+
Yes. DP appears in 15 reported problems and two of the top patterns (Partition Equal Subset Sum and Minimum Window Subsequence) are medium-to-hard DP. You don't need to be a DP wizard, but you must recognize subset-sum, unbounded knapsack, and string-matching DP shapes before the OA.
Should I study hash tables before or after strings?+
Study them in parallel. Hash tables (20 problems) overlap heavily with string work: Group Anagrams, LRU Cache, and Open the Lock all use hash-based logic. Mastering hash tables lets you solve string problems faster. You can't skip either one.
What's the hardest problem type I'll face?+
Minimum Window Subsequence and Word Ladder are both reported hard problems that combine strings, DP or BFS, and sliding-window logic. They're not unsolvable, but they demand composing multiple techniques. LRU Cache (medium) is also deceptively tricky because it requires design thinking on top of hash-table and linked-list skills.
How much time should I spend on sorting and two-pointers?+
Less than arrays or DP, but don't skip it. Sorting and two-pointers appear in 12 and 8 problems respectively. Greedy array problems like Minimize Maximum Pair Sum lean on sorting and two-pointers. Spend 3 to 4 hours on this topic after you've locked down arrays and strings.