HashedIn coding interview
questions, leaked.
23 problems reported across recent HashedIn interviews. Top patterns: array, dynamic programming, greedy. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
HashedIn's assessment leans hard on arrays and dynamic programming. Out of 23 problems reported, 18 are array-based and 9 involve DP patterns. You're looking at mostly medium difficulty with a sprinkling of hard problems that combine multiple topics in one. The good news: arrays are drillable. The reality: by interview day, you won't have seen every permutation. If you blank on a DP recurrence or array pattern mid-assessment, StealthCoder runs invisibly and surfaces a working solution in seconds, keeping you moving.
Top problems at HashedIn
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Find Candidates for Data Scientist Position | EASY | 100.0 | 76% | Database |
| 02 | Maximize Items | HARD | 100.0 | 75% | Database |
| 03 | Maximum Points Inside the Square | MEDIUM | 100.0 | 38% | Array · Hash Table · String |
| 04 | Count the Number of Powerful Integers | HARD | 83.0 | 47% | Math · String · Dynamic Programming |
| 05 | Minimize Length of Array Using Operations | MEDIUM | 83.0 | 35% | Array · Math · Greedy |
| 06 | Maximum Subarray | MEDIUM | 70.5 | 52% | Array · Divide and Conquer · Dynamic Programming |
| 07 | Best Time to Buy and Sell Stock | EASY | 70.5 | 55% | Array · Dynamic Programming |
| 08 | Trapping Rain Water | HARD | 70.5 | 65% | Array · Two Pointers · Dynamic Programming |
| 09 | Container With Most Water | MEDIUM | 60.6 | 58% | Array · Two Pointers · Greedy |
| 10 | Minimum Cost to Make Array Equal | HARD | 60.6 | 46% | Array · Binary Search · Greedy |
| 11 | Next Permutation | MEDIUM | 60.6 | 43% | Array · Two Pointers |
| 12 | Chalkboard XOR Game | HARD | 60.6 | 63% | Array · Math · Bit Manipulation |
| 13 | Jump Game II | MEDIUM | 60.6 | 42% | Array · Dynamic Programming · Greedy |
| 14 | Edit Distance | MEDIUM | 60.6 | 59% | String · Dynamic Programming |
| 15 | 3Sum | MEDIUM | 60.6 | 37% | Array · Two Pointers · Sorting |
| 16 | Maximum Product Subarray | MEDIUM | 60.6 | 35% | Array · Dynamic Programming |
| 17 | Minimum Time to Repair Cars | MEDIUM | 60.6 | 60% | Array · Binary Search |
| 18 | Group Anagrams | MEDIUM | 60.6 | 71% | Array · Hash Table · String |
| 19 | Isomorphic Strings | EASY | 60.6 | 47% | Hash Table · String |
| 20 | Number of Islands | MEDIUM | 60.6 | 62% | Array · Depth-First Search · Breadth-First Search |
| 21 | Beautiful Arrangement | MEDIUM | 60.6 | 65% | Array · Dynamic Programming · Backtracking |
| 22 | Jump Game | MEDIUM | 60.6 | 39% | Array · Dynamic Programming · Greedy |
| 23 | Koko Eating Bananas | MEDIUM | 60.6 | 49% | Array · Binary 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 HashedIn 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- array18 · 78%
- dynamic programming9 · 39%
- greedy5 · 22%
- string5 · 22%
- two pointers4 · 17%
- binary search4 · 17%
- sorting4 · 17%
- math3 · 13%
- hash table3 · 13%
- bit manipulation2 · 9%
Arrays dominate the assessment, but they're not isolated. Most array problems are layered with secondary patterns: two-pointers, greedy, binary search, or DP. This means you can't just memorize classic array tricks. You need to recognize when a problem wants a sliding window versus when it wants you to build a prefix sum or sort the input first. DP appears in 9 problems and pairs frequently with arrays and strings. Greedy and two-pointers show up in medium difficulty problems where the greedy choice isn't obvious at first glance. Database and bit manipulation are low-frequency outliers, but problems like "Chalkboard XOR Game" and "Maximize Items" suggest they test game-theory and math reasoning alongside code. If you haven't practiced the interaction between array manipulation and DP, that's your weak spot. StealthCoder is the safety net if you hit a hybrid problem that doesn't fit your drills.
Companies with similar patterns
If you prepped for HashedIn, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass HashedIn.
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.
HashedIn interview FAQ
Should I study dynamic programming or arrays first for HashedIn?+
Start with arrays since 18 of 23 problems touch them. But don't drill arrays in isolation. Focus on problems that combine arrays with greedy, two-pointers, or DP. "Jump Game II" and "Trapping Rain Water" are representative. Once you can identify the pattern, DP becomes clearer.
How many two-pointer problems should I solve before the assessment?+
Two-pointers appear in 4 reported problems, often paired with arrays or sorting. "Container With Most Water" and "3Sum" are classics. Solve 5 to 8 two-pointer problems to build intuition. The hard part isn't the technique, it's recognizing when to use it.
Is binary search important for HashedIn?+
It appears in 4 problems, mostly in medium difficulty and often combined with sorting or greedy. "Minimum Cost to Make Array Equal" is a good example. If you're short on time, don't prioritize it over array and DP, but don't skip it entirely.
What about string and database problems?+
String appears in 5 problems, usually paired with DP or math (like "Count the Number of Powerful Integers"). Database shows up in 2 problems but they're outliers. If you're weak on SQL, they're a lower return on effort than mastering array patterns.
How do I prepare for hard problems like Trapping Rain Water?+
HashedIn's hard problems mix arrays, DP, and often a second technique like two-pointers or monotonic stacks. "Trapping Rain Water" hits all of these. Practice medium array problems first, then attempt hards only after you can quickly spot when DP or greedy is needed.