Zenefits coding interview
questions, leaked.
21 problems reported across recent Zenefits interviews. Top patterns: array, breadth first search, string. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Zenefits asks 21 problems across their OA, split roughly even between medium and hard difficulty with a cluster of easy warmups. Arrays dominate the list (9 problems), followed by BFS and string manipulation. You'll see patterns like sliding windows, two pointers, and graph traversal show up repeatedly. If you haven't touched problems like Sliding Window Maximum or Shortest Distance from All Buildings, you're walking in blind. StealthCoder runs invisibly during the live assessment and surfaces working code the moment you hit a wall, which matters when you're grinding through hard problems back-to-back.
Top problems at Zenefits
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Majority Element | EASY | 100.0 | 66% | Array · Hash Table · Divide and Conquer |
| 02 | Median of Two Sorted Arrays | HARD | 97.6 | 44% | Array · Binary Search · Divide and Conquer |
| 03 | Excel Sheet Column Title | EASY | 97.6 | 44% | Math · String |
| 04 | Shortest Distance from All Buildings | HARD | 97.6 | 44% | Array · Breadth-First Search · Matrix |
| 05 | Flatten 2D Vector | MEDIUM | 97.6 | 50% | Array · Two Pointers · Design |
| 06 | Valid Palindrome | EASY | 97.6 | 51% | Two Pointers · String |
| 07 | N-Queens II | HARD | 97.6 | 77% | Backtracking |
| 08 | Sliding Window Maximum | HARD | 97.6 | 48% | Array · Queue · Sliding Window |
| 09 | Convert Sorted List to Binary Search Tree | MEDIUM | 97.6 | 64% | Linked List · Divide and Conquer · Tree |
| 10 | Trapping Rain Water | HARD | 97.6 | 65% | Array · Two Pointers · Dynamic Programming |
| 11 | Majority Element II | MEDIUM | 97.6 | 54% | Array · Hash Table · Sorting |
| 12 | Graph Valid Tree | MEDIUM | 97.6 | 49% | Depth-First Search · Breadth-First Search · Union Find |
| 13 | Min Stack | MEDIUM | 97.6 | 56% | Stack · Design |
| 14 | Generate Parentheses | MEDIUM | 97.6 | 77% | String · Dynamic Programming · Backtracking |
| 15 | Valid Parentheses | EASY | 97.6 | 42% | String · Stack |
| 16 | Course Schedule II | MEDIUM | 97.6 | 53% | Depth-First Search · Breadth-First Search · Graph |
| 17 | LRU Cache | MEDIUM | 97.6 | 45% | Hash Table · Linked List · Design |
| 18 | Course Schedule | MEDIUM | 97.6 | 49% | Depth-First Search · Breadth-First Search · Graph |
| 19 | Reverse Linked List | EASY | 97.6 | 79% | Linked List · Recursion |
| 20 | Number of Islands | MEDIUM | 97.6 | 62% | Array · Depth-First Search · Breadth-First Search |
| 21 | Verify Preorder Sequence in Binary Search Tree | MEDIUM | 97.6 | 51% | Array · Stack · Tree |
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 Zenefits OA. The proctor cannot see it. Screen share cannot detect it. Built because the OA filter rejects engineers who'd pass the on-site. That's a broken filter. This is the workaround.
Get StealthCoder- array9 · 43%
- breadth first search5 · 24%
- string4 · 19%
- stack4 · 19%
- depth first search4 · 19%
- hash table3 · 14%
- divide and conquer3 · 14%
- two pointers3 · 14%
- design3 · 14%
- linked list3 · 14%
Array problems are your baseline. Master Majority Element, Trapping Rain Water, and the 2D vector iterator before you interview. BFS and DFS are nearly tied (5 and 4 problems), so graph traversal isn't optional. String work clusters around validation and generation (Valid Parentheses, Generate Parentheses, Valid Palindrome). The hard problems here are genuinely hard: Median of Two Sorted Arrays, N-Queens II, Sliding Window Maximum. Most candidates crater on one. Stack and queue problems require clean implementation. Hash tables appear less often (3 times) but pair with array problems. If you blank mid-OA on a monotonic stack or backtracking pattern you haven't drilled, StealthCoder gives you the fix in seconds without the proctor knowing.
Companies with similar patterns
If you prepped for Zenefits, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Zenefits.
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 because the OA filter rejects engineers who'd pass the on-site. That's a broken filter. This is the workaround. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Zenefits interview FAQ
Should I study arrays first for Zenefits?+
Yes. Nine of 21 problems touch arrays, including Majority Element, Trapping Rain Water, and Sliding Window Maximum. Start there, then move to BFS and string work. You can't afford to be weak on the pattern that shows up in 43% of their assessment.
How many hard problems will I see?+
Exactly 5 out of 21. Median of Two Sorted Arrays, Shortest Distance from All Buildings, N-Queens II, Sliding Window Maximum, and Trapping Rain Water are all hard. The rest are medium or easy. Hard problems eat time, so drill them separately from warm-ups.
Do I need to master graph problems for Zenefits?+
Graph problems appear in 6 of 21 questions when you count BFS and DFS separately. Graph Valid Tree and shortest-path variants will come up. You don't need advanced graph theory, but you need clean BFS and DFS implementations.
Is two-pointers a common technique here?+
Three problems explicitly use two-pointers (Valid Palindrome, Flatten 2D Vector, Trapping Rain Water). It's a supporting pattern, not the main event. But it pairs with array and string problems constantly, so practice the mechanic.
What should I do if I get stuck on a hard problem during the OA?+
Most candidates don't solve all 5 hard problems clean. If you blank on Sliding Window Maximum or Trapping Rain Water, that's when you need a backup. You can't afford to stare at the screen for 10 minutes.