Folders and files
| Name | Name | Last commit date | ||
|---|---|---|---|---|
A complete collection of essential Data Structures & Algorithms patterns with clean, well-explained code examples to master problem-solving code examples to master problem-solving and crack MAANG interviews. Covers core patterns like Sliding Window,Two Pointers,DP, Graphs and Backtracking with templates,complexity notes and practical interview tips
- About the Repository
- Core Concepts
- Popular DSA Patterns
- MAANG-Level Problem Set
- Company-Wise Patterns
- Contributing
- Resources & References
- Author
This repository is a comprehensive collection of essential Data Structures & Algorithms (DSA) patterns, designed to help you master problem-solving and crack interviews at MAANG, Swiggy, Zomato, and top startups.
Each pattern comes with:
- 🧩 Code templates in Python, C++, or Java
- 🧠 Explanation of core logic
- ⏱️ Time and Space Complexity
- 🏹 Real-world interview problems
Before diving into patterns, review these fundamental areas:
- Arrays & Strings
- Recursion & Backtracking
- Linked Lists, Stacks, Queues
- Trees & Graphs
- Dynamic Programming
- Sorting & Searching
- Greedy Algorithms
- Bit Manipulation
| Pattern | Description | Example Problems |
|---|---|---|
| 🪟 Sliding Window | Optimize subarray problems for max/min/sum/k-length | Longest Substring Without Repeating Characters (LeetCode #3), Max Consecutive Ones, Minimum Window Substring |
| 🎯 Two Pointers | Works on sorted data to find pairs, partitions | 3Sum, Container With Most Water, Remove Duplicates from Sorted Array |
| 🧮 Binary Search | Efficient searching or optimization | Search Rotated Array, Find Peak Element, Median of Two Sorted Arrays |
| 🧵 Fast & Slow Pointers | Detect loops or middle nodes | Linked List Cycle, Palindrome Linked List |
| 🔁 Dynamic Programming | Break down complex problems into subproblems | Longest Increasing Subsequence, House Robber, Coin Change |
| 🌳 Trees & Graphs (DFS/BFS) | Hierarchical and connected data traversal | Binary Tree Level Order, Clone Graph, Word Ladder |
| 🎲 Backtracking | Generate all combinations or paths | N-Queens, Sudoku Solver, Permutations |
| 🧭 Greedy | Local optimal → global optimal | Jump Game, Interval Scheduling, Huffman Encoding |
| 🧮 Prefix Sum / Kadane’s | Efficient range calculations | Maximum Subarray, Subarray Sum Equals K |
| 🧱 Stack & Monotonic Stack | Useful in range problems | Largest Rectangle in Histogram, Daily Temperatures |
- Longest Substring Without Repeating Characters – Google, Amazon
👉 Use hash map to track characters; move window start as duplicates appear.
⏱ O(N) - Minimum Window Substring – Meta, Microsoft
👉 Maintain counts of target chars and shrink window.
⏱ O(N)
- Container With Most Water – Amazon, Netflix
👉 Use pointers at both ends; move smaller height inward.
⏱ O(N) - 3Sum Problem – Google, Meta
👉 Sort + Two Pointers from both ends to find zero-sum triplets.
⏱ O(N²)
- Coin Change – Amazon, Meta
👉 Classic DP to find min coins for target sum.
⏱ O(N * amount) - Longest Increasing Subsequence – Google, Netflix
👉 Use DP with binary search for O(N log N).
- Word Ladder – Google, Swiggy
👉 BFS transformation sequence between words.
⏱ O(N * L²) - Clone Graph – Meta
👉 DFS clone with hash map to prevent duplication.
- N-Queens – Amazon, Zomato
👉 Recursive placement with column and diagonal checks.
⏱ O(N!) - Permutations – Netflix, Google
👉 Swap and explore recursively.
⏱ O(N!)
- Jump Game – Amazon
👉 Track maximum reachable index at each step.
⏱ O(N) - Activity Selection – Zomato, Swiggy
👉 Sort by end times; pick non-overlapping activities.
⏱ O(N log N)
| Company | Common Patterns | Example Problems |
|---|---|---|
| Amazon | Sliding Window, Greedy, Trees | LRU Cache, Jump Game, Binary Tree Zigzag |
| Graphs, DP, Backtracking | Word Ladder, N-Queens, LIS | |
| Meta | Two Pointers, Hashing, DP | 3Sum, Clone Graph, Coin Change |
| Netflix | Binary Search, Greedy | Container With Most Water, Meeting Rooms II |
| Swiggy | Graphs, Greedy, BFS | Minimum Path Delivery, Word Ladder |
| Zomato | DP, Sorting, Greedy | Restaurant Allocation, Activity Scheduling |
Contributions are welcome!
- Fork this repository
- Create a new branch (feature/new-pattern)
- Add explanations or code samples
- Submit a pull request 🚀
Pawan Kumar
📍 Product Manager | Data & DevOps Mentor | AI & Cloud Enthusiast
🔗 LinkedIn
✉️ pawankm7654@gmail.com
⭐ Star this repository if it helped you — it motivates to add more curated interview content every week!