A curated collection of coding, system design, and ML interview questions from top tech companies.
Continuously updated with 2025-2026 interview questions across 17+ companies.
Problem Collections
- NeetCode 150 - Essential Problems for FAANG Interviews
- Blind 75 - The Ultimate Interview Preparation List
- Top 75 LeetCode Questions to Crack The Coding Interviews
Company-Specific Questions
AI & Machine Learning
- LLM Papers Cheatsheet - Essential Research Papers
- Complete ML Interview Preparation Guide
- Guide to Building AI Agents
Programming Resources
Company Questions
| SNo. | Company |
|---|---|
| 1. | FAANG Must Do Problems |
| 2. | |
| 3. | Meta (Facebook) |
| 4. | Amazon |
| 5. | Apple |
| 6. | Netflix |
| 7. | Microsoft |
| 8. | |
| 9. | OpenAI |
| 10. | Anthropic |
| 11. | Palantir |
| 12. | Databricks |
| 13. | Stripe |
| 14. | NVIDIA |
| 15. | Uber |
| 16. | ByteDance / TikTok |
| 17. | Flipkart |
Beginner Track (0-3 months)
- Start with Blind 75 for fundamentals
- Practice 2-3 problems daily focusing on patterns
- Review Python Resources for clean code
Intermediate Track (1-6 months)
- Complete NeetCode 150 for comprehensive coverage
- Focus on Recent FAANG/MAANG Questions
- Start System Design preparation
Advanced Track (Targeting specific roles)
- Review company-specific sections below
- Practice ML Interview Questions for ML roles
- Study AI/LLM Papers for AI/research roles
View Problems
| No. | Problem | Difficulty | Time Complexity | Space Complexity |
|---|---|---|---|---|
| 1 | Two Sum | Easy | O(n) | O(n) |
| 2 | Longest Substring Without Repeating Characters | Medium | O(n) | O(min(m,n)) |
| 3 | Longest Palindromic Substring | Medium | O(nΒ²) | O(1) |
| 4 | Container With Most Water | Medium | O(n) | O(1) |
| 5 | 3Sum | Medium | O(nΒ²) | O(1) |
| 6 | Remove Nth Node From End of List | Medium | O(n) | O(1) |
| 7 | Valid Parentheses | Easy | O(n) | O(n) |
| 8 | Merge Two Sorted Lists | Easy | O(n+m) | O(1) |
| 9 | Merge k Sorted Lists | Hard | O(n log k) | O(1) |
| 10 | Search in Rotated Sorted Array | Medium | O(log n) | O(1) |
| 11 | Combination Sum | Medium | O(2βΏ) | O(n) |
| 12 | Rotate Image | Medium | O(nΒ²) | O(1) |
| 13 | Group Anagrams | Medium | O(n k log k) | O(n k) |
| 14 | Maximum Subarray | Easy | O(n) | O(1) |
| 15 | Spiral Matrix | Medium | O(mΓn) | O(1) |
| 16 | Jump Game | Medium | O(n) | O(1) |
| 17 | Merge Intervals | Medium | O(n log n) | O(n) |
| 18 | Insert Interval | Medium | O(n) | O(n) |
| 19 | Unique Paths | Medium | O(mΓn) | O(mΓn) |
| 20 | Climbing Stairs | Easy | O(n) | O(1) |
| 21 | Set Matrix Zeroes | Medium | O(mΓn) | O(1) |
| 22 | Minimum Window Substring | Hard | O(n) | O(k) |
| 23 | Word Search | Medium | O(mΓnΓ4α΅) | O(k) |
| 24 | Decode Ways | Medium | O(n) | O(n) |
| 25 | Validate Binary Search Tree | Medium | O(n) | O(h) |
| 26 | Same Tree | Easy | O(n) | O(h) |
| 27 | Binary Tree Level Order Traversal | Medium | O(n) | O(n) |
| 28 | Maximum Depth of Binary Tree | Easy | O(n) | O(h) |
| 29 | Construct Binary Tree from Preorder and Inorder Traversal | Medium | O(n) | O(n) |
| 30 | Best Time to Buy and Sell Stock | Easy | O(n) | O(1) |
View 35 Problems (2025-2026 Most Frequent)
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Two Sum | Easy | Hash Map / Arrays |
| 2 | Number of Islands | Medium | Graph / DFS |
| 3 | Merge Intervals | Medium | Intervals / Sorting |
| 4 | LRU Cache | Medium | Design / Linked List |
| 5 | Validate Binary Search Tree | Medium | Trees / BST |
| 6 | Course Schedule II | Medium | Graph / Topological Sort |
| 7 | Longest Substring Without Repeating Characters | Medium | Sliding Window |
| 8 | Trapping Rain Water | Hard | Two Pointers / Stack |
| 9 | Serialize and Deserialize Binary Tree | Hard | Trees / Design |
| 10 | Kth Largest Element in an Array | Medium | Heap / Quickselect |
| 11 | Median of Two Sorted Arrays | Hard | Binary Search |
| 12 | Group Anagrams | Medium | Hashing / Strings |
| 13 | Word Ladder | Hard | BFS / Graphs |
| 14 | Merge K Sorted Lists | Hard | Heap / Linked List |
| 15 | Container With Most Water | Medium | Two Pointers |
| 16 | Top K Frequent Elements | Medium | Heap / Hashing |
| 17 | Coin Change | Medium | Dynamic Programming |
| 18 | Search in Rotated Sorted Array | Medium | Binary Search |
| 19 | Product of Array Except Self | Medium | Arrays / Prefix |
| 20 | Binary Tree Level Order Traversal | Medium | Trees / BFS |
| 21 | Combination Sum | Medium | Backtracking |
| 22 | Edit Distance | Hard | Dynamic Programming |
| 23 | Minimum Window Substring | Hard | Sliding Window |
| 24 | Implement Trie (Prefix Tree) | Medium | Trie |
| 25 | Accounts Merge | Medium | Union-Find |
| 26 | Sliding Window Maximum | Hard | Monotonic Deque |
| 27 | The Skyline Problem | Hard | Heap / Divide and Conquer |
| 28 | Largest Rectangle in Histogram | Hard | Monotonic Stack |
| 29 | Word Search II | Hard | Trie / Backtracking |
| 30 | Rotting Oranges | Medium | Graph / BFS |
| 31 | Critical Connections in a Network | Hard | Graph / Tarjan's |
| 32 | Pacific Atlantic Water Flow | Medium | Graph / Multi-source BFS |
| 33 | Network Delay Time | Medium | Graph / Dijkstra |
| 34 | Daily Temperatures | Medium | Monotonic Stack |
| 35 | Find the Safest Path in a Grid | Medium | BFS / Binary Search |
View 35 Problems (2025-2026 Most Frequent)
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Minimum Remove to Make Valid Parentheses | Medium | Stack / String |
| 2 | Binary Tree Vertical Order Traversal | Medium | Tree / BFS |
| 3 | Basic Calculator II | Medium | Stack / Expression Parsing |
| 4 | Valid Palindrome II | Easy | Two Pointers / String |
| 5 | Kth Largest Element in an Array | Medium | Heap / Divide & Conquer |
| 6 | Lowest Common Ancestor of a Binary Tree | Medium | Tree / DFS |
| 7 | Random Pick with Weight | Medium | Binary Search / Prefix Sum |
| 8 | Subarray Sum Equals K | Medium | Array / HashMap / Prefix Sum |
| 9 | Valid Palindrome | Easy | Two Pointers / String |
| 10 | Two Sum | Easy | Array / HashMap |
| 11 | Binary Tree Right Side View | Medium | Tree / BFS |
| 12 | Top K Frequent Elements | Medium | Heap / HashMap |
| 13 | Merge Intervals | Medium | Array / Sorting |
| 14 | LRU Cache | Medium | Design / HashMap / Linked List |
| 15 | Clone Graph | Medium | Graph / BFS / DFS |
| 16 | Merge k Sorted Lists | Hard | Linked List / Heap |
| 17 | Maximum Swap | Medium | Math / Greedy |
| 18 | Number of Islands | Medium | Graph / DFS / BFS |
| 19 | Accounts Merge | Medium | Union-Find / Graph |
| 20 | Diameter of Binary Tree | Easy | Tree / DFS |
| 21 | Product of Array Except Self | Medium | Array / Prefix Sum |
| 22 | Word Break | Medium | Dynamic Programming |
| 23 | Copy List with Random Pointer | Medium | Linked List / Hash Table |
| 24 | Making a Large Island | Hard | Graph / DFS / Union-Find |
| 25 | Expression Add Operators | Hard | Backtracking / Math |
| 26 | Valid Word Abbreviation | Easy | String / Parsing |
| 27 | Lowest Common Ancestor of a Binary Tree III | Medium | Tree / Hash Table |
| 28 | Convert BST to Sorted Doubly Linked List | Medium | Tree / Linked List |
| 29 | K Closest Points to Origin | Medium | Heap / Math |
| 30 | Interval List Intersections | Medium | Two Pointers / Intervals |
| 31 | Simplify Path | Medium | Stack / String |
| 32 | Insert Delete GetRandom O(1) | Medium | Design / Hash Table |
| 33 | Sliding Window Maximum | Hard | Monotonic Deque |
| 34 | Regular Expression Matching | Hard | DP / Recursion |
| 35 | All Nodes Distance K in Binary Tree | Medium | Tree / BFS |
View 33 Problems (2025-2026 Most Frequent)
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Two Sum | Easy | Array / Hash Table |
| 2 | Number of Islands | Medium | Graph / DFS / BFS |
| 3 | LRU Cache | Medium | Design / Hash + Linked List |
| 4 | Merge Intervals | Medium | Array / Sorting |
| 5 | Group Anagrams | Medium | Hashing / Strings |
| 6 | Top K Frequent Elements | Medium | Heap / Hashing |
| 7 | Task Scheduler | Medium | Heap / Greedy |
| 8 | Trapping Rain Water | Hard | Two Pointers / Stack |
| 9 | Product of Array Except Self | Medium | Array / Prefix Sum |
| 10 | Longest Substring Without Repeating Characters | Medium | Sliding Window |
| 11 | Minimum Window Substring | Hard | Sliding Window |
| 12 | Kth Largest Element in an Array | Medium | Heap / Quickselect |
| 13 | Merge k Sorted Lists | Hard | Heap / Linked List |
| 14 | Course Schedule | Medium | Graph / Topological Sort |
| 15 | Rotting Oranges | Medium | Graph / BFS |
| 16 | Serialize and Deserialize Binary Tree | Hard | Trees / Design |
| 17 | Lowest Common Ancestor of a Binary Tree | Medium | Trees / DFS |
| 18 | Coin Change | Medium | Dynamic Programming |
| 19 | Best Time to Buy and Sell Stock | Easy | Array / DP |
| 20 | Sliding Window Maximum | Hard | Deque / Sliding Window |
| 21 | Reorganize String | Medium | Heap / Greedy |
| 22 | Insert Delete GetRandom O(1) | Medium | Design / Hash Table |
| 23 | Decode String | Medium | Stack / Strings |
| 24 | Koko Eating Bananas | Medium | Binary Search |
| 25 | Largest Rectangle in Histogram | Hard | Monotonic Stack |
| 26 | Car Pooling | Medium | Array / Prefix Sum |
| 27 | Meeting Rooms III | Hard | Heap / Sorting |
| 28 | K Closest Points to Origin | Medium | Heap / Math |
| 29 | Valid Parentheses | Easy | Stack / String |
| 30 | Word Search | Medium | Backtracking / Matrix |
| 31 | Course Schedule II | Medium | Graph / Topological Sort |
| 32 | Design Hit Counter | Medium | Design / Queue |
| 33 | Min Stack | Medium | Stack / Design |
View 20 Problems (2025-2026 Most Frequent)
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Two Sum | Easy | Array / Hash Table |
| 2 | LRU Cache | Medium | Design / Hash + Linked List |
| 3 | Number of Islands | Medium | Graph / DFS / BFS |
| 4 | Reverse Linked List | Easy | Linked List |
| 5 | Group Anagrams | Medium | String / Hash Table |
| 6 | Valid Parentheses | Easy | Stack / String |
| 7 | Merge Intervals | Medium | Array / Sorting |
| 8 | Word Break | Medium | Dynamic Programming |
| 9 | Product of Array Except Self | Medium | Array / Prefix Sum |
| 10 | Best Time to Buy and Sell Stock | Easy | Array / DP |
| 11 | 3Sum | Medium | Array / Two Pointers |
| 12 | Trapping Rain Water | Hard | Two Pointers / Stack |
| 13 | Top K Frequent Elements | Medium | Heap / Hash Table |
| 14 | Course Schedule | Medium | Graph / Topological Sort |
| 15 | Lowest Common Ancestor of a Binary Tree | Medium | Tree / DFS |
| 16 | Serialize and Deserialize Binary Tree | Hard | Tree / Design |
| 17 | Longest Substring Without Repeating Characters | Medium | Sliding Window |
| 18 | Median of Two Sorted Arrays | Hard | Binary Search |
| 19 | Maximum Profit in Job Scheduling | Hard | Binary Search / DP |
| 20 | Bus Routes | Hard | Graph / BFS |
View 15 Problems (2025-2026 Most Frequent)
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | LRU Cache | Medium | Design / Hash + Linked List |
| 2 | Merge Intervals | Medium | Array / Sorting |
| 3 | Course Schedule II | Medium | Graph / Topological Sort |
| 4 | Top K Frequent Elements | Medium | Heap / Hash Table |
| 5 | Network Delay Time | Medium | Graph / Dijkstra |
| 6 | Daily Temperatures | Medium | Monotonic Stack |
| 7 | Number of Islands | Medium | Graph / DFS / BFS |
| 8 | Serialize and Deserialize Binary Tree | Hard | Tree / Design |
| 9 | Find Median from Data Stream | Hard | Heap / Design |
| 10 | Trapping Rain Water | Hard | Two Pointers / Stack |
| 11 | Edit Distance | Medium | Dynamic Programming |
| 12 | Minimum Window Substring | Hard | Sliding Window |
| 13 | Meeting Rooms II | Medium | Intervals / Heap |
| 14 | Koko Eating Bananas | Medium | Binary Search |
| 15 | Implement Trie (Prefix Tree) | Medium | Trie / Design |
View 20 Problems (2025-2026 Most Frequent)
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Two Sum | Easy | Array / Hash Table |
| 2 | LRU Cache | Medium | Design / Hash + Linked List |
| 3 | Longest Substring Without Repeating Characters | Medium | Sliding Window |
| 4 | Add Two Numbers | Medium | Linked List / Math |
| 5 | Number of Islands | Medium | Graph / DFS / BFS |
| 6 | Maximum Subarray | Medium | Array / DP |
| 7 | Merge Two Sorted Lists | Easy | Linked List |
| 8 | Copy List with Random Pointer | Medium | Linked List / Hash Table |
| 9 | Rotate Image | Medium | Array / Matrix |
| 10 | Set Matrix Zeroes | Medium | Array / Matrix |
| 11 | Clone Graph | Medium | Graph / DFS / BFS |
| 12 | Binary Tree Level Order Traversal | Medium | Tree / BFS |
| 13 | Median of Two Sorted Arrays | Hard | Binary Search |
| 14 | Regular Expression Matching | Hard | DP / Recursion |
| 15 | Reverse Nodes in k-Group | Hard | Linked List |
| 16 | Asteroid Collision | Medium | Stack |
| 17 | Cheapest Flights Within K Stops | Medium | Graph / DP / BFS |
| 18 | Construct Binary Tree from Preorder and Inorder Traversal | Medium | Tree / Divide and Conquer |
| 19 | Largest Rectangle in Histogram | Hard | Monotonic Stack |
| 20 | Sudoku Solver | Hard | Backtracking / Matrix |
View 20 Problems (2025-2026 Most Frequent)
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Nested List Weight Sum | Medium | DFS / Recursion |
| 2 | Nested List Weight Sum II | Medium | Stack / DFS |
| 3 | Can Place Flowers | Easy | Array / Greedy |
| 4 | Find Leaves of Binary Tree | Medium | Tree / DFS |
| 5 | Max Stack | Hard | Stack / Linked List / Design |
| 6 | All O'one Data Structure | Hard | Hash Table / Linked List / Design |
| 7 | Shortest Word Distance II | Medium | Hash Table / Design |
| 8 | Find the Celebrity | Medium | Two Pointers / Graph |
| 9 | Maximum Subarray | Medium | Array / DP |
| 10 | Maximum Product Subarray | Medium | Array / DP |
| 11 | Merge Intervals | Medium | Array / Sorting |
| 12 | Edit Distance | Medium | Dynamic Programming |
| 13 | Design Add and Search Words Data Structure | Medium | Trie / Design |
| 14 | Word Ladder | Hard | BFS / Graphs |
| 15 | Insert Delete GetRandom O(1) | Medium | Design / Hash Table |
| 16 | Valid Parentheses | Easy | Stack / String |
| 17 | Isomorphic Strings | Easy | String / Hash Table |
| 18 | Decode Ways | Medium | Dynamic Programming |
| 19 | House Robber II | Medium | Dynamic Programming |
| 20 | Combination Sum II | Medium | Backtracking |
View 20 Problems (2025-2026 -- Production-Oriented)
OpenAI interviews focus on practical engineering over LeetCode puzzles. Problems are drawn from a bank of ~8 core challenges with progressive difficulty layers. Python is strongly recommended.
Core Custom Problems (Most Frequently Reported)
| No. | Problem | Difficulty | Category | Context |
|---|---|---|---|---|
| 1 | KV Store Serialize/Deserialize | Hard | Design / Strings | Multi-part: basic serialization, file persistence, multithreading, versioned store |
| 2 | CD Directory Navigation | Hard | String / Path Resolution | Implement cd() with relative/absolute paths, .., ., ~, symlink cycle detection |
| 3 | Excel/Spreadsheet Engine | Hard | Graph / Design | getCell() O(1), setCell() with formula dependencies, circular dependency detection |
| 4 | In-Memory Database | Hard | Database Design | select() with WHERE, AND, ORDER BY, comparison operators -- no SQL parsing |
| 5 | Resumable Iterator | Hard | Iterator / State | Stateful iterator with getState()/setState(), nested structures, async variants |
| 6 | Async Node Counting | Hard | Distributed / Trees | Count tree nodes using only async parent-child messaging |
LeetCode-Equivalent Problems
| No. | Problem | Difficulty | Category | Context |
|---|---|---|---|---|
| 7 | LRU Cache | Medium | Design | Inference KV cache -- most frequently reported |
| 8 | Time Based Key-Value Store | Medium | Design / Binary Search | Model checkpoint storage |
| 9 | Snapshot Array | Medium | Design / Binary Search | Model state checkpointing |
| 10 | Alien Dictionary | Hard | Graph / Topological Sort | Tokenizer ordering |
| 11 | Web Crawler Multithreaded | Medium | Concurrency / BFS | Training data crawling |
| 12 | LFU Cache | Hard | Design | Advanced caching |
| 13 | Decode String | Medium | Stack / Strings | String processing |
| 14 | Word Ladder | Hard | BFS / Graphs | NLP transformations |
| 15 | Design Memory Allocator | Medium | Design / Simulation | GPU memory management |
| 16 | Game of Life | Medium | Simulation / Matrix | Extended to infinite board |
| 17 | Meeting Rooms II | Medium | Intervals / Heap | Interval scheduling |
| 18 | Serialize and Deserialize Binary Tree | Hard | Trees / Design | Data persistence |
| 19 | Top K Frequent Elements | Medium | Heap / Hash | ML preprocessing |
| 20 | Course Schedule II | Medium | Graph / Topological Sort | Dependency resolution |
View Interview Guide (2025-2026 -- Custom Problems + Concurrency Round)
Anthropic uses CodeSignal OA (60-90 min) followed by a 4-6 hour onsite with 4-6 rounds. Python expected. AI tools strictly prohibited. Problems are drawn from a bank of ~6 core custom challenges with progressive difficulty layers.
Core Custom Coding Problems (Most Frequently Reported)
| No. | Problem | Difficulty | Category | Context |
|---|---|---|---|---|
| 1 | In-Memory Database | Hard | Design | 4 levels: SET/GET/DELETE -> filtered scans -> TTL -> backup/restore |
| 2 | Web Crawler | Hard | BFS / Concurrency | BFS crawl -> multithreaded/async optimization |
| 3 | LRU Cache (Bugfix + Extend) | Hard | Design / Debugging | Fix bugs, add persistence, handle *args/**kwargs |
| 4 | Stack Trace / Profiler | Hard | Parsing / Design | Convert sampling data to chronological events |
| 5 | Tokenization Engine | Hard | String / NLP | Code review, tokenize/detokenize with vocabulary coverage |
| 6 | Distributed Mode/Median | Hard | Distributed Systems | Compute across 10 nodes with bandwidth constraints |
LeetCode Practice Problems (Mapped to Anthropic's Focus Areas)
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | LRU Cache | Medium | Design |
| 2 | Web Crawler Multithreaded | Medium | Concurrency / BFS |
| 3 | Implement Trie (Prefix Tree) | Medium | Trie / NLP |
| 4 | Word Break | Medium | DP / Strings |
| 5 | Design Hit Counter | Medium | Design |
| 6 | Time Based Key-Value Store | Medium | Design / Binary Search |
| 7 | Serialize and Deserialize Binary Tree | Hard | Trees / Design |
| 8 | Merge k Sorted Lists | Hard | Heap / Distributed |
| 9 | Course Schedule II | Medium | Graph / Topological Sort |
| 10 | Number of Islands | Medium | Graph / DFS |
Key Focus Areas: AI safety/alignment (Constitutional AI, RLHF, red-teaming), systems engineering (distributed training, inference optimization), concurrency/parallel programming, Transformer architecture depth
View 20 Problems + Unique Interview Format (2025-2026)
Palantir's onsite gives you 3 of 4 round types: Decomposition, System Design, Re-engineering (Debugging), and Coding. Each round includes 20 min of behavioral questions.
Most Frequently Asked Coding Problems
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Merge Intervals | Medium | Intervals / Sorting |
| 2 | Number of Islands | Medium | Graph / DFS / BFS |
| 3 | LRU Cache | Medium | Design / Hash Map |
| 4 | Course Schedule | Medium | Graph / Topological Sort |
| 5 | Course Schedule II | Medium | Graph / Topological Sort |
| 6 | All Ancestors of a Node in DAG | Medium | Graph / DFS |
| 7 | Merge k Sorted Lists | Hard | Heap / Linked List |
| 8 | Trapping Rain Water | Hard | Two Pointers / Stack |
| 9 | Regular Expression Matching | Hard | DP / String |
| 10 | Subdomain Visit Count | Medium | Hash Map / String |
| 11 | Find the Celebrity | Medium | Array / Logic |
| 12 | UTF-8 Validation | Medium | Bit Manipulation |
| 13 | Container With Most Water | Medium | Two Pointers |
| 14 | Max Area of Island | Medium | Graph / DFS |
| 15 | Rotate Image | Medium | Array / Matrix |
| 16 | Integer to English Words | Hard | String / Math |
| 17 | Shortest Path to Get All Keys | Hard | BFS / Bitmask |
| 18 | Construct Quad Tree | Medium | Tree / Recursion |
| 19 | Inorder Successor in BST | Medium | Tree / BST |
| 20 | Contains Duplicate III | Hard | BST / Bucket Sort |
Unique Interview Rounds
- Decomposition: Break down open-ended real-world problems (e.g., "Design tech to help elderly cook safely"). Non-coding.
- Re-engineering (Debugging): Debug 500-1000 lines of buggy code with red herrings
- System Design: Focus on data integration, ontology design, access control (ABAC)
- FDSE vs SWE: Forward-deployed roles emphasize client-facing scenarios; backend roles emphasize scale
View 25 Problems (2025-2026 Most Frequent -- includes dedicated concurrency round)
Databricks has a unique dedicated concurrency/multithreading round (1 hour). OA is 4 problems in 70 minutes on CodeSignal.
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Capacity To Ship Packages Within D Days | Medium | Binary Search |
| 2 | Trapping Rain Water | Hard | Two Pointers / Stack |
| 3 | Max Stack | Hard | Stack / Linked List / Design |
| 4 | All O'one Data Structure | Hard | Hash Table / Design |
| 5 | Word Break | Medium | DP / Trie |
| 6 | Rotting Oranges | Medium | BFS / Matrix |
| 7 | All Nodes Distance K in Binary Tree | Medium | Tree / BFS / DFS |
| 8 | Decode String | Medium | Stack / Recursion |
| 9 | K Closest Points to Origin | Medium | Heap / Math |
| 10 | Asteroid Collision | Medium | Stack |
| 11 | Design Hit Counter | Medium | Design / Queue |
| 12 | Time Based Key-Value Store | Medium | Design / Binary Search |
| 13 | Snapshot Array | Medium | Design / Binary Search |
| 14 | Find All Anagrams in a String | Medium | Sliding Window |
| 15 | Cheapest Flights Within K Stops | Medium | Graph / BFS / DP |
| 16 | Binary Search Tree Iterator | Medium | Stack / Tree / Design |
| 17 | House Robber | Medium | Dynamic Programming |
| 18 | Interval List Intersections | Medium | Two Pointers |
| 19 | Print in Order | Easy | Concurrency |
| 20 | Print FooBar Alternately | Medium | Concurrency |
| 21 | Building H2O | Medium | Concurrency |
| 22 | The Dining Philosophers | Medium | Concurrency |
| 23 | Course Schedule II | Medium | Graph / Topological Sort |
| 24 | Alien Dictionary | Hard | Graph / Topological Sort |
| 25 | Median of Two Sorted Arrays | Hard | Binary Search |
View 15 Problems + Unique Interview Format (2025-2026)
Stripe does NOT use traditional LeetCode-style interviews. Problems model real engineering work -- payment processing, debugging, API integration. Code quality valued over algorithmic cleverness. Unique rounds: Bug Squash (debug a GitHub repo), Integration (build with Stripe API), API Design (REST resource modeling).
LeetCode-Mapped Practice Problems
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Two Sum | Easy | Hash Map (transaction matching) |
| 2 | LRU Cache | Medium | Design (caching patterns) |
| 3 | Merge Intervals | Medium | Intervals (batch scheduling) |
| 4 | Design Hit Counter | Medium | Design (rate limiting) |
| 5 | Top K Frequent Elements | Medium | Heap (merchant ranking) |
| 6 | Subarray Sum Equals K | Medium | Prefix Sum (revenue calc) |
| 7 | Time Based Key-Value Store | Medium | Design / Binary Search |
| 8 | Course Schedule | Medium | Graph / Cycle Detection |
| 9 | Sliding Window Maximum | Hard | Deque (event log analysis) |
| 10 | Serialize and Deserialize Binary Tree | Hard | Design (JSON parsing) |
| 11 | Coin Change | Medium | DP (fee calculation) |
| 12 | Group Anagrams | Medium | Hashing / Strings |
| 13 | Product of Array Except Self | Medium | Arrays / Prefix |
| 14 | Longest Substring Without Repeating Characters | Medium | Sliding Window |
| 15 | Number of Islands | Medium | Graph / DFS |
Custom Problems: Invoice reconciliation (CSV parsing), request deduplication (idempotency), webhook handler debugging, payment retry logic with exponential backoff, shipping cost calculator with progressive complexity
View 20 Problems (2025-2026 -- GPU/Performance Focus)
NVIDIA interviews emphasize performance awareness (cache hierarchies, memory bandwidth, parallelization). After solving the baseline, expect: "How does this behave under memory pressure? How would you parallelize across 10,000 threads?" C++ essential for systems/GPU roles.
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Maximum Number of Events That Can Be Attended | Medium | Greedy / Heap |
| 2 | Min Stack | Medium | Stack / Design |
| 3 | Clone Graph | Medium | Graph / DFS |
| 4 | K Closest Points to Origin | Medium | Heap / Math |
| 5 | Random Pick with Weight | Medium | Binary Search / Prefix Sum |
| 6 | Trapping Rain Water | Hard | Two Pointers / Stack |
| 7 | Number of Islands | Medium | Graph / DFS / BFS |
| 8 | Rotate Image | Medium | Array / Matrix |
| 9 | Word Break | Medium | Dynamic Programming |
| 10 | Shortest Path in Binary Matrix | Medium | BFS / Graph |
| 11 | Design HashMap | Easy | Design / Hash Table |
| 12 | Longest Increasing Path in a Matrix | Hard | DFS / DP / Topological Sort |
| 13 | Permutation in String | Medium | Sliding Window |
| 14 | Expression Add Operators | Hard | Backtracking / Math |
| 15 | Binary Search Tree Iterator | Medium | Tree / Stack |
| 16 | Word Ladder II | Hard | BFS / DFS / Backtracking |
| 17 | Bus Routes | Hard | BFS / Graph |
| 18 | Making A Large Island | Hard | DFS / Union Find |
| 19 | Line Reflection | Medium | Hash Table / Math |
| 20 | Missing Ranges | Easy | Array / String |
CUDA/GPU-Specific: Matrix multiplication optimization (GEMM), CUDA kernel fusion, memory coalescing analysis, thread synchronization across blocks, multi-GPU communication patterns
View 20 Problems (2025-2026 -- Domain-Driven)
Uber interviews reflect the product domain -- routing, dispatch, surge pricing map to graph traversal, streaming aggregation, and sliding-window patterns. Code readability is explicitly evaluated.
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Maximize Amount After Two Days of Conversions | Medium | Graph / BFS |
| 2 | Bus Routes | Hard | Graph / BFS |
| 3 | Alien Dictionary | Hard | Topological Sort |
| 4 | Number of Islands II | Hard | Union Find |
| 5 | Design Hit Counter | Medium | Design / Sliding Window |
| 6 | Number of Islands | Medium | Graph / DFS |
| 7 | Spiral Matrix | Medium | Matrix / Array |
| 8 | Word Search | Medium | Backtracking / DFS |
| 9 | LRU Cache | Medium | Design / HashMap + Linked List |
| 10 | Top K Frequent Elements | Medium | Heap / Bucket Sort |
| 11 | Evaluate Division | Medium | Graph / Weighted |
| 12 | Construct Quad Tree | Medium | Divide and Conquer |
| 13 | Random Pick with Weight | Medium | Prefix Sum / Binary Search |
| 14 | Find Median from Data Stream | Hard | Two Heaps / Design |
| 15 | Merge Intervals | Medium | Sorting / Greedy |
| 16 | Meeting Rooms II | Medium | Heap / Intervals |
| 17 | Course Schedule | Medium | Graph / Cycle Detection |
| 18 | Course Schedule II | Medium | Graph / Topological Sort |
| 19 | Longest Subarray With Absolute Diff <= Limit | Medium | Sliding Window / Monotonic Deque |
| 20 | Squares of a Sorted Array | Easy | Two Pointers |
Custom Problems: Expiry counter (TTL-based sessions), driver-rider matching engine, surge pricing calculator (real-time supply/demand), adaptive bitrate selector
View 20 Problems (2025-2026 -- High Difficulty)
ByteDance interviews are among the most technically demanding in the industry. Baseline is Medium, Hard is frequent. Candidates solve 2-3 problems per round (vs 1-2 at Google/Meta). Interviewers progressively modify problems to increase difficulty in real-time. Compile-ready, bug-free code expected.
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Implement Queue using Stacks | Easy | Stack / Queue / Design |
| 2 | Daily Temperatures | Medium | Monotonic Stack |
| 3 | Merge k Sorted Lists | Hard | Linked List / Heap |
| 4 | LRU Cache | Medium | Design / Hash + Linked List |
| 5 | Max Consecutive Ones III | Medium | Sliding Window |
| 6 | Sliding Window Maximum | Hard | Deque / Sliding Window |
| 7 | Number of Islands | Medium | Graph / DFS / BFS |
| 8 | Search in Rotated Sorted Array | Medium | Binary Search |
| 9 | Binary Tree Maximum Path Sum | Hard | Tree / DFS |
| 10 | Trapping Rain Water | Hard | Two Pointers / DP |
| 11 | Course Schedule II | Medium | Graph / Topological Sort |
| 12 | 3Sum | Medium | Two Pointers / Array |
| 13 | Longest Valid Parentheses | Hard | Stack / DP |
| 14 | N-Queens | Hard | Backtracking |
| 15 | Serialize and Deserialize Binary Tree | Hard | Tree / Design |
| 16 | Kth Largest Element in an Array | Medium | Heap / Quickselect |
| 17 | Coin Change | Medium | Dynamic Programming |
| 18 | Regular Expression Matching | Hard | DP / String |
| 19 | Longest Increasing Path in a Matrix | Hard | DFS / DP / Topological Sort |
| 20 | Minimum Difference in Sums After Removal of Elements | Hard | Heap / Greedy |
Custom Problems: Video chunk scheduler, hashtag trend detector (sliding window on streams), comment tree flattening, content moderation priority queue, video deduplication via hashing
View Problems
| No. | Problem | Difficulty | Category |
|---|---|---|---|
| 1 | Add Two Numbers | Medium | Linked List / Math |
This repository covers 600+ coding problems across 17+ companies, organized by company and topic. Includes NeetCode 150, Blind 75, system design guides, and ML/AI interview resources.
Complete System Design Interview Guide - 25 system design problems with complexity ratings and company tags.
Contributions are welcome. Please feel free to submit a pull request with new questions, corrections, or additional company coverage.
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