Two Sigma coding interview
questions, leaked.
23 problems reported across recent Two Sigma interviews. Top patterns: array, dynamic programming, string. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Two Sigma's assessment hits you with 23 problems across four difficulty tiers, but the distribution is deceptive. Thirteen are medium, six are hard, and arrays dominate the problem set at 65% of all questions you'll see. You're looking at classic array manipulation paired with dynamic programming, binary search, and string work. The real threat isn't breadth, it's depth on array patterns and the hard problems that chain multiple concepts together. If you blank on a circular subarray or string-matching problem mid-OA, StealthCoder surfaces a working solution in seconds, invisible to the proctor.
Top problems at Two Sigma
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Minimum Operations to Reduce an Integer to 0 | MEDIUM | 100.0 | 57% | Dynamic Programming · Greedy · Bit Manipulation |
| 02 | Number of Provinces | MEDIUM | 100.0 | 69% | Depth-First Search · Breadth-First Search · Union Find |
| 03 | Random Pick with Weight | MEDIUM | 98.1 | 48% | Array · Math · Binary Search |
| 04 | Maximum Subarray Sum with One Deletion | MEDIUM | 96.0 | 45% | Array · Dynamic Programming |
| 05 | Multiply Strings | MEDIUM | 93.8 | 42% | Math · String · Simulation |
| 06 | Longest String Chain | MEDIUM | 93.8 | 62% | Array · Hash Table · Two Pointers |
| 07 | Wildcard Matching | HARD | 93.8 | 30% | String · Dynamic Programming · Greedy |
| 08 | Power of Four | EASY | 93.8 | 49% | Math · Bit Manipulation · Recursion |
| 09 | Maximum Sum Circular Subarray | MEDIUM | 93.8 | 48% | Array · Divide and Conquer · Dynamic Programming |
| 10 | Intersection of Two Arrays | EASY | 93.8 | 76% | Array · Hash Table · Two Pointers |
| 11 | Game of Life | MEDIUM | 93.8 | 71% | Array · Matrix · Simulation |
| 12 | Word Search II | HARD | 91.3 | 37% | Array · String · Backtracking |
| 13 | Parallel Courses III | HARD | 72.1 | 67% | Array · Dynamic Programming · Graph |
| 14 | Merge k Sorted Lists | HARD | 72.1 | 57% | Linked List · Divide and Conquer · Heap (Priority Queue) |
| 15 | Minimum Space Wasted From Packaging | HARD | 65.3 | 33% | Array · Binary Search · Sorting |
| 16 | Design Memory Allocator | MEDIUM | 65.3 | 48% | Array · Hash Table · Design |
| 17 | Design HashMap | EASY | 65.3 | 66% | Array · Hash Table · Linked List |
| 18 | Search Suggestions System | MEDIUM | 55.7 | 65% | Array · String · Binary Search |
| 19 | Sum of Square Numbers | MEDIUM | 55.7 | 37% | Math · Two Pointers · Binary Search |
| 20 | Design Tic-Tac-Toe | MEDIUM | 55.7 | 59% | Array · Hash Table · Design |
| 21 | Robot Room Cleaner | HARD | 55.7 | 78% | Backtracking · Interactive |
| 22 | Best Time to Buy and Sell Stock | EASY | 55.7 | 55% | Array · Dynamic Programming |
| 23 | Meeting Rooms II | MEDIUM | 55.7 | 52% | Array · Two Pointers · Greedy |
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 Two Sigma OA. The proctor cannot see it. Screen share cannot detect it. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage.
Get StealthCoder- array15 · 65%
- dynamic programming7 · 30%
- string5 · 22%
- binary search5 · 22%
- sorting5 · 22%
- hash table5 · 22%
- math4 · 17%
- simulation4 · 17%
- two pointers4 · 17%
- matrix3 · 13%
Two Sigma's problem set clusters hard around arrays (15 problems) with dynamic programming (7) as the secondary pattern. String problems (5), binary search (5), and hash tables (5) round out the core. Six of the 23 problems are hard, and they're not gentle: Wildcard Matching, Word Search II, and Parallel Courses III all require you to chain DP or backtracking with greedy thinking or graph logic. Start with the 13 medium problems to build fluency on circular subarrays, string chains, and greedy deletions. The medium tier teaches you array rhythm and DP substructure. Hard problems are where candidates lose time. Merging sorted lists, topological sort on graphs, and trie-based search require multiple pattern recognition steps. StealthCoder is your hedge if the interview flips to a variant you haven't drilled or your DP recurrence doesn't click under time pressure.
Companies with similar patterns
If you prepped for Two Sigma, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Two Sigma.
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 by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Two Sigma interview FAQ
How many array problems should I drill before the Two Sigma OA?+
Two Sigma's problem set is 65% array-based (15 of 23). Drill all 15 if you have a week. If you have three days, focus on the top problems: Maximum Sum Circular Subarray, Maximum Subarray Sum with One Deletion, and Minimum Operations to Reduce an Integer to 0. These three cover the most common patterns.
Should I prioritize dynamic programming or arrays?+
Arrays first. Fifteen array problems dominate the list, but seven of them also require DP. Start with pure array work (circular subarray, two-pointer patterns), then move to DP overlaps like Maximum Subarray Sum with One Deletion and Longest String Chain. This order builds momentum.
Are the six hard problems worth practicing before the OA?+
Yes. Hard problems make up 26% of Two Sigma's set. Word Search II, Wildcard Matching, and Parallel Courses III are likely scenarios. Practice at least three hard problems from the list. If you hit one live and blank, it's worth 20-30% of your score and where StealthCoder earns its place.
Is binary search critical for Two Sigma?+
It appears five times in the problem list, often nested inside larger problems like Random Pick with Weight and Minimum Space Wasted From Packaging. You don't need to master binary search in isolation, but practice it paired with array manipulation and prefix sums.
What's the hardest topic combination I'll face?+
String plus DP plus backtracking. Wildcard Matching and Word Search II combine all three. These are hard-tier problems that candidates often timeout on. If you run out of prep time, these are the two where a real-time solution tool makes the biggest difference.