Instacart coding interview
questions, leaked.
15 problems reported across recent Instacart interviews. Top patterns: array, sorting, string. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Instacart's coding assessments hit hard on array manipulation and sorting. Out of 15 problems in their reported question pool, 12 center on arrays, and you'll see sorting show up in at least 5. The difficulty split is 4 easy, 8 medium, 3 hard. The median problem is a medium that chains array logic with greedy or sorting. You can't memorize your way through this one. If you freeze mid-assessment on an interval or greedy problem, StealthCoder runs invisible during screen share and hands you the working solution in seconds.
Top problems at Instacart
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Time Based Key-Value Store | MEDIUM | 100.0 | 49% | Hash Table · String · Binary Search |
| 02 | Check if Every Row and Column Contains All Numbers | EASY | 96.4 | 53% | Array · Hash Table · Matrix |
| 03 | Find First and Last Position of Element in Sorted Array | MEDIUM | 79.6 | 47% | Array · Binary Search |
| 04 | Squares of a Sorted Array | EASY | 74.9 | 73% | Array · Two Pointers · Sorting |
| 05 | Wildcard Matching | HARD | 68.7 | 30% | String · Dynamic Programming · Greedy |
| 06 | Average Waiting Time | MEDIUM | 60.1 | 73% | Array · Simulation |
| 07 | Valid Number | HARD | 60.1 | 22% | String |
| 08 | Minimum Number of Arrows to Burst Balloons | MEDIUM | 60.1 | 60% | Array · Greedy · Sorting |
| 09 | Maximum Number of Events That Can Be Attended | MEDIUM | 60.1 | 33% | Array · Greedy · Sorting |
| 10 | Search Insert Position | EASY | 60.1 | 49% | Array · Binary Search |
| 11 | Valid Sudoku | MEDIUM | 60.1 | 62% | Array · Hash Table · Matrix |
| 12 | Non-overlapping Intervals | MEDIUM | 60.1 | 56% | Array · Dynamic Programming · Greedy |
| 13 | Merge Intervals | MEDIUM | 60.1 | 49% | Array · Sorting |
| 14 | Best Time to Buy and Sell Stock | EASY | 60.1 | 55% | Array · Dynamic Programming |
| 15 | Word Search II | HARD | 60.1 | 37% | Array · String · Backtracking |
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 Instacart OA. The proctor cannot see it. Screen share cannot detect it. Built by an engineer at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share.
Get StealthCoder- array12 · 80%
- sorting5 · 33%
- string4 · 27%
- greedy4 · 27%
- binary search3 · 20%
- hash table3 · 20%
- matrix3 · 20%
- dynamic programming3 · 20%
- simulation1 · 7%
- two pointers1 · 7%
Array problems dominate Instacart interviews for a reason: they test your ability to manipulate data structures under constraint, exactly what their logistics platform does. Sorting and greedy algorithms appear together in at least 4 problems (Minimum Arrows, Maximum Events, Non-overlapping Intervals, Merge Intervals), so learn to spot interval problems fast. Hash tables and binary search each show up 3 times, often paired with arrays. String problems are fewer (4 total) but all hard or medium. Spend your prep time on array patterns first, then greedy + sorting combinations. Know binary search cold. If you haven't drilled interval merging and arrow-burst style problems, that's where StealthCoder becomes your safety net on the live assessment.
Companies with similar patterns
If you prepped for Instacart, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Instacart.
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 at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Instacart interview FAQ
How many array problems should I solve before the Instacart assessment?+
Since 12 of their 15 reported problems involve arrays, aim for 20 to 30 array problems minimum. Focus on sorting-based arrays, interval problems, and greedy array challenges. The difficulty skews medium, so don't skip hard problems like Word Search II and Wildcard Matching.
Should I study dynamic programming or greedy first for Instacart?+
Greedy comes first. It appears in 4 of their top problems and pairs directly with sorting and arrays. DP shows up 3 times, often as a secondary tag. Get comfortable with greedy interval and scheduling problems before diving into DP edge cases.
Is binary search important for Instacart coding interviews?+
Yes. Three of their reported problems require binary search, and two involve sorted arrays where binary search is the optimal choice. Know Time Based Key-Value Store and Find First and Last Position cold. Binary search appears in at least 20% of their assessments.
What's the hardest topic I'll face on Instacart's assessment?+
Wildcard Matching and Word Search II are both hard problems that layer string, recursion, and backtracking. Valid Number is also hard and tests your ability to parse string logic carefully. These three are lower frequency but high difficulty. If you hit one, StealthCoder solves it invisibly during screen share.
How much time should I spend on hash tables and matrix problems?+
Hash tables and matrices each appear 3 times in their problem pool. Hash tables are often paired with arrays or strings, so they're worth understanding but not your primary focus. Matrices appear in 2 validation-style problems. Allocate time after you've drilled arrays, sorting, and greedy.