Pinterest coding interview
questions, leaked.
49 problems reported across recent Pinterest interviews. Top patterns: array, string, sorting. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Pinterest's interview hits you with 49 problems across 6 rounds, and 38 of them are medium-to-hard. You'll face array manipulation constantly (32 problems), then strings and sorting (13 each), hash tables (12), and graph traversal (BFS/DFS combined, 19 problems). One problem is easy; don't count on it. You have maybe a week to drill the patterns that matter. If you blank mid-assessment on a hash-table or backtracking problem, StealthCoder runs invisibly and surfaces a working solution in seconds while the proctor sees nothing but your screen.
Top problems at Pinterest
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Count and Say | MEDIUM | 100.0 | 61% | String |
| 02 | Reconstruct Itinerary | HARD | 94.8 | 44% | Depth-First Search · Graph · Eulerian Circuit |
| 03 | Shortest Path in a Grid with Obstacles Elimination | HARD | 93.4 | 46% | Array · Breadth-First Search · Matrix |
| 04 | Optimal Account Balancing | HARD | 92.4 | 50% | Array · Dynamic Programming · Backtracking |
| 05 | Count Subarrays With Score Less Than K | HARD | 90.8 | 62% | Array · Binary Search · Sliding Window |
| 06 | Maximum Profit in Job Scheduling | HARD | 89.6 | 54% | Array · Binary Search · Dynamic Programming |
| 07 | Bus Routes | HARD | 85.7 | 47% | Array · Hash Table · Breadth-First Search |
| 08 | Expression Add Operators | HARD | 85.0 | 42% | Math · String · Backtracking |
| 09 | Find Median from Data Stream | HARD | 78.8 | 53% | Two Pointers · Design · Sorting |
| 10 | Shortest Way to Form String | MEDIUM | 76.6 | 61% | Two Pointers · String · Binary Search |
| 11 | Is Subsequence | EASY | 74.2 | 48% | Two Pointers · String · Dynamic Programming |
| 12 | Reorganize String | MEDIUM | 72.8 | 56% | Hash Table · String · Greedy |
| 13 | Design Search Autocomplete System | HARD | 69.8 | 49% | String · Depth-First Search · Design |
| 14 | Longest Word in Dictionary | MEDIUM | 69.8 | 53% | Array · Hash Table · String |
| 15 | Find Median Given Frequency of Numbers | HARD | 66.2 | 42% | Database |
| 16 | Jump Game III | MEDIUM | 64.2 | 66% | Array · Depth-First Search · Breadth-First Search |
| 17 | Coin Change | MEDIUM | 61.9 | 46% | Array · Dynamic Programming · Breadth-First Search |
| 18 | Find K-th Smallest Pair Distance | HARD | 61.9 | 46% | Array · Two Pointers · Binary Search |
| 19 | Meeting Rooms III | HARD | 59.2 | 44% | Array · Hash Table · Sorting |
| 20 | String Compression | MEDIUM | 59.2 | 58% | Two Pointers · String |
| 21 | Sparse Matrix Multiplication | MEDIUM | 59.2 | 69% | Array · Hash Table · Matrix |
| 22 | Target Sum | MEDIUM | 56.2 | 51% | Array · Dynamic Programming · Backtracking |
| 23 | Unique Paths II | MEDIUM | 56.2 | 43% | Array · Dynamic Programming · Matrix |
| 24 | Minimize Result by Adding Parentheses to Expression | MEDIUM | 52.7 | 68% | String · Enumeration |
| 25 | Employee Free Time | HARD | 48.3 | 73% | Array · Line Sweep · Sorting |
| 26 | Is Graph Bipartite? | MEDIUM | 48.3 | 58% | Depth-First Search · Breadth-First Search · Union Find |
| 27 | Unique Paths III | HARD | 48.3 | 82% | Array · Backtracking · Bit Manipulation |
| 28 | The Number of Weak Characters in the Game | MEDIUM | 48.3 | 44% | Array · Stack · Greedy |
| 29 | Split Array Largest Sum | HARD | 42.7 | 58% | Array · Binary Search · Dynamic Programming |
| 30 | Accounts Merge | MEDIUM | 42.7 | 60% | Array · Hash Table · String |
| 31 | Combination Sum | MEDIUM | 42.7 | 75% | Array · Backtracking |
| 32 | Top K Frequent Elements | MEDIUM | 42.7 | 65% | Array · Hash Table · Divide and Conquer |
| 33 | Letter Combinations of a Phone Number | MEDIUM | 42.7 | 64% | Hash Table · String · Backtracking |
| 34 | Single Element in a Sorted Array | MEDIUM | 42.7 | 59% | Array · Binary Search |
| 35 | Meeting Rooms II | MEDIUM | 42.7 | 52% | Array · Two Pointers · Greedy |
| 36 | Possible Bipartition | MEDIUM | 42.7 | 52% | Depth-First Search · Breadth-First Search · Union Find |
| 37 | Multiply Strings | MEDIUM | 42.7 | 42% | Math · String · Simulation |
| 38 | Find Minimum Time to Finish All Jobs | HARD | 34.9 | 44% | Array · Dynamic Programming · Backtracking |
| 39 | Snakes and Ladders | MEDIUM | 34.9 | 48% | Array · Breadth-First Search · Matrix |
| 40 | Shortest Path to Get All Keys | HARD | 34.9 | 54% | Array · Bit Manipulation · Breadth-First Search |
| 41 | Number of Islands | MEDIUM | 34.9 | 62% | Array · Depth-First Search · Breadth-First Search |
| 42 | Implement Trie (Prefix Tree) | MEDIUM | 34.9 | 68% | Hash Table · String · Design |
| 43 | Sudoku Solver | HARD | 34.9 | 64% | Array · Hash Table · Backtracking |
| 44 | The Maze | MEDIUM | 34.9 | 60% | Array · Depth-First Search · Breadth-First Search |
| 45 | Find the Celebrity | MEDIUM | 34.9 | 48% | Two Pointers · Graph · Interactive |
| 46 | Find First and Last Position of Element in Sorted Array | MEDIUM | 34.9 | 47% | Array · Binary Search |
| 47 | Dot Product of Two Sparse Vectors | MEDIUM | 34.9 | 90% | Array · Hash Table · Two Pointers |
| 48 | Candy Crush | MEDIUM | 34.9 | 77% | Array · Two Pointers · Matrix |
| 49 | Smallest Range Covering Elements from K Lists | HARD | 34.9 | 70% | Array · Hash Table · 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 Pinterest 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- array32 · 65%
- string13 · 27%
- sorting13 · 27%
- hash table12 · 24%
- breadth first search11 · 22%
- matrix10 · 20%
- two pointers9 · 18%
- backtracking8 · 16%
- depth first search8 · 16%
- dynamic programming8 · 16%
Arrays dominate the diet. Learn subarray patterns, two-pointer sweeps, and prefix sums first because they show up in easy wins and hard problems alike. Sorting and hash tables are your second wave. BFS and DFS are structural checkpoints for graph and matrix problems (11 and 8 problems respectively). The hard problems cluster around two big themes: dynamic programming (often paired with binary search or bitmask) and design-y backtracking (Reconstruct Itinerary, Expression Add Operators, Optimal Account Balancing). You're not expected to nail all 19 hard problems in prep. Drill the medium tier hard (like Reorganize String, Maximum Profit in Job Scheduling) first. For the hard outliers you haven't seen, StealthCoder is your safety net during the live assessment.
Companies with similar patterns
If you prepped for Pinterest, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Pinterest.
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.
Pinterest interview FAQ
How many array problems should I solve before the Pinterest interview?+
Arrays appear in 32 of 49 problems. Start with two-pointer and subarray patterns (Count Subarrays With Score Less Than K, sliding window). Aim for 15 to 20 variations before the OA. Combine with binary search and sorting for harder array-based problems.
Should I spend time on string problems if I'm running short?+
Strings hit 13 problems and often pair with hash tables or backtracking. Focus on Reorganize String and Expression Add Operators first. They're medium-to-hard and test realistic string manipulation. Skip the isolated string drills if time is tight.
Is graph knowledge essential for Pinterest?+
Graph problems (BFS, DFS, Eulerian Circuit) account for about 19 of the 49. Reconstruct Itinerary and Bus Routes are hard and test graph traversal depth. Master BFS/DFS on grids and basic graph structure. You can't skip this.
How much dynamic programming do I need?+
Eight problems touch DP, and most are hard. Optimal Account Balancing, Maximum Profit in Job Scheduling, and Find Median from Data Stream are the gatekeepers. Pair DP with binary search and bitmask drills. Medium DP reps first, then tackle hard variants.
What topic should I drill first if I have one week?+
Arrays and two-pointers. They're foundational for 32 problems and intersect with sorting, binary search, and strings. Spend days one to three here. Move to graphs (BFS/DFS) on days four to five, then DP and backtracking for days six to seven.