DoorDash coding interview
questions, leaked.
88 problems reported across recent DoorDash 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.
DoorDash's assessment hits you with 88 problems, split heavily toward medium and hard. You're looking at 53 medium problems and 29 hard ones, which means they're not testing if you can solve easy stuff fast. Arrays dominate the list (54 problems), but strings, hash tables, BFS, and DFS are all frequent enough that you can't skip them. You'll see real problems like Walls and Gates, Binary Tree Maximum Path Sum, and Longest Increasing Path in a Matrix. If you blank mid-assessment, StealthCoder runs invisibly and surfaces a working solution in seconds.
Top problems at DoorDash
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Walls and Gates | MEDIUM | 100.0 | 63% | Array · Breadth-First Search · Matrix |
| 02 | Binary Tree Maximum Path Sum | HARD | 95.3 | 41% | Dynamic Programming · Tree · Depth-First Search |
| 03 | Longest Increasing Path in a Matrix | HARD | 92.4 | 55% | Array · Dynamic Programming · Depth-First Search |
| 04 | Maximum Profit in Job Scheduling | HARD | 87.1 | 54% | Array · Binary Search · Dynamic Programming |
| 05 | Search Suggestions System | MEDIUM | 82.2 | 65% | Array · String · Binary Search |
| 06 | Koko Eating Bananas | MEDIUM | 79.5 | 49% | Array · Binary Search |
| 07 | Design File System | MEDIUM | 75.3 | 64% | Hash Table · String · Design |
| 08 | Most Profit Assigning Work | MEDIUM | 75.3 | 56% | Array · Two Pointers · Binary Search |
| 09 | Check if One String Swap Can Make Strings Equal | EASY | 74.4 | 49% | Hash Table · String · Counting |
| 10 | Shortest Distance from All Buildings | HARD | 72.9 | 44% | Array · Breadth-First Search · Matrix |
| 11 | Single-Threaded CPU | MEDIUM | 70.6 | 46% | Array · Sorting · Heap (Priority Queue) |
| 12 | Minimum Number of Steps to Make Two Strings Anagram | MEDIUM | 70.6 | 82% | Hash Table · String · Counting |
| 13 | Find K Closest Elements | MEDIUM | 69.3 | 49% | Array · Two Pointers · Binary Search |
| 14 | Next Greater Element III | MEDIUM | 66.5 | 35% | Math · Two Pointers · String |
| 15 | Buddy Strings | EASY | 66.5 | 34% | Hash Table · String |
| 16 | Design In-Memory File System | HARD | 64.9 | 48% | Hash Table · String · Design |
| 17 | Making A Large Island | HARD | 64.0 | 55% | Array · Depth-First Search · Breadth-First Search |
| 18 | Basic Calculator III | HARD | 64.0 | 52% | Math · String · Stack |
| 19 | Find Nearest Point That Has the Same X or Y Coordinate | EASY | 64.0 | 69% | Array |
| 20 | Count Sub Islands | MEDIUM | 63.1 | 73% | Array · Depth-First Search · Breadth-First Search |
| 21 | Count Nodes With the Highest Score | MEDIUM | 62.2 | 51% | Array · Tree · Depth-First Search |
| 22 | Asteroid Collision | MEDIUM | 62.2 | 46% | Array · Stack · Simulation |
| 23 | Serialize and Deserialize Binary Tree | HARD | 60.1 | 59% | String · Tree · Depth-First Search |
| 24 | Basic Calculator II | MEDIUM | 56.5 | 46% | Math · String · Stack |
| 25 | Count All Valid Pickup and Delivery Options | HARD | 56.5 | 65% | Math · Dynamic Programming · Combinatorics |
| 26 | Course Schedule II | MEDIUM | 55.0 | 53% | Depth-First Search · Breadth-First Search · Graph |
| 27 | Vertical Order Traversal of a Binary Tree | HARD | 55.0 | 51% | Hash Table · Tree · Depth-First Search |
| 28 | Best Meeting Point | HARD | 55.0 | 61% | Array · Math · Sorting |
| 29 | Implement Trie (Prefix Tree) | MEDIUM | 53.5 | 68% | Hash Table · String · Design |
| 30 | Two Sum | EASY | 53.5 | 56% | Array · Hash Table |
| 31 | Immediate Food Delivery II | MEDIUM | 53.5 | 54% | Database |
| 32 | Immediate Food Delivery I | EASY | 53.5 | 81% | Database |
| 33 | Jump Game | MEDIUM | 51.8 | 39% | Array · Dynamic Programming · Greedy |
| 34 | Interval List Intersections | MEDIUM | 51.8 | 73% | Array · Two Pointers · Line Sweep |
| 35 | Subsequence With the Minimum Score | HARD | 51.8 | 33% | Two Pointers · String · Binary Search |
| 36 | Mice and Cheese | MEDIUM | 51.8 | 47% | Array · Greedy · Sorting |
| 37 | Largest Rectangle in Histogram | HARD | 50.0 | 47% | Array · Stack · Monotonic Stack |
| 38 | Basic Calculator | HARD | 50.0 | 46% | Math · String · Stack |
| 39 | Task Scheduler | MEDIUM | 50.0 | 62% | Array · Hash Table · Greedy |
| 40 | 01 Matrix | MEDIUM | 47.9 | 51% | Array · Dynamic Programming · Breadth-First Search |
| 41 | Word Search II | HARD | 45.6 | 37% | Array · String · Backtracking |
| 42 | Max Area of Island | MEDIUM | 45.6 | 73% | Array · Depth-First Search · Breadth-First Search |
| 43 | Next Permutation | MEDIUM | 45.6 | 43% | Array · Two Pointers |
| 44 | Minimum Size Subarray Sum | MEDIUM | 42.9 | 49% | Array · Binary Search · Sliding Window |
| 45 | Longest Common Subsequence | MEDIUM | 42.9 | 58% | String · Dynamic Programming |
| 46 | Number of Visible People in a Queue | HARD | 42.9 | 71% | Array · Stack · Monotonic Stack |
| 47 | Swim in Rising Water | HARD | 42.9 | 63% | Array · Binary Search · Depth-First Search |
| 48 | Design Add and Search Words Data Structure | MEDIUM | 39.7 | 47% | String · Depth-First Search · Design |
| 49 | Sudoku Solver | HARD | 39.7 | 64% | Array · Hash Table · Backtracking |
| 50 | Jump Game II | MEDIUM | 39.7 | 42% | Array · Dynamic Programming · 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 DoorDash 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- array54 · 61%
- string24 · 27%
- hash table23 · 26%
- breadth first search22 · 25%
- depth first search22 · 25%
- sorting19 · 22%
- matrix17 · 19%
- heap priority queue14 · 16%
- design12 · 14%
- binary search10 · 11%
Array problems are your bread and butter here, but don't treat that as permission to ignore the rest. Strings show up in 24 problems, hash tables in 23, and BFS/DFS each appear in 22. That's a tight cluster. The hard problems lean into dynamic programming and matrix traversal, so if you get one of those, you need to recognize the pattern instantly. Sorting and binary search matter too (19 and 10 problems respectively), especially since they show up together in problems like Maximum Profit in Job Scheduling and Koko Eating Bananas. You'll see design questions (Design File System), which test whether you can structure data cleanly. Drill arrays and strings first, then lock in BFS/DFS and DP for the hard stuff. StealthCoder is your hedge if you hit a matrix-DP hybrid you haven't seen before and you're running out of time.
Companies with similar patterns
If you prepped for DoorDash, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass DoorDash.
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.
DoorDash interview FAQ
How many array problems should I solve before my DoorDash OA?+
At least 20 to 25. Arrays appear in 54 of the 88 problems reported, so they're your foundation. Focus on subarrays, sliding window, and two-pointer patterns first since those show up across multiple problems like Find K Closest Elements and Most Profit Assigning Work.
Is it worth drilling string problems for DoorDash?+
Yes. Strings appear in 24 problems and often pair with hash tables or binary search. Problems like Check if One String Swap Can Make Strings Equal and Search Suggestions System test both string manipulation and pattern recognition. Spend 4 to 5 hours on them.
What should I study first, BFS or DFS?+
Either. Both appear in 22 problems each. Start with whichever feels more intuitive, but know both equally well. Walls and Gates is a pure BFS problem, while Binary Tree Maximum Path Sum requires DFS. You'll see them both on test day.
How hard are DoorDash's hard problems?+
Hard. 29 out of 88 are hard-tier, including Longest Increasing Path in a Matrix and Binary Tree Maximum Path Sum, both of which combine DP with traversal. You won't see easy wins there. If you don't recognize the pattern in the first minute, you'll run out of time.
Do I need to study design problems?+
Yes, but don't overweight it. Design appears in 12 problems, and Design File System is on the list. It tests your ability to pick the right data structure (hash table, trie) and build clean code. Spend 2 to 3 hours on 3 to 4 design problems.