Hi there! 👋 This repository is a collection of DSA patterns and problems I personally used to prepare for software engineering internships like:
- Google STEP
- Microsoft Explore
- Meta University
- Amazon SDE Intern
- And more!
It’s designed to be simple, practical, and organized by topic, so you can focus on mastering the right patterns without getting overwhelmed.
- 📂 Go through the folders by topic (e.g., Sliding Window, BFS, etc.)
- ✅ Use the checklists to track your progress.
- 💡 Most problems are from LeetCode and are chosen for interview relevance.
- ✍️ Feel free to fork, modify, or contribute!
dsa-prep
│
├── 01_prefix_sum
├── 02_two_pointers
├── 03_sliding_window
├── 04_fast_slow_pointers
├── 05_linked_list_reversal
├── 06_monotonic_stack
├── 07_top_k_heap
├── 08_intervals
├── 09_binary_search_variants
├── 10_binary_tree_traversals
├── 11_dfs
├── 12_bfs
├── 13_matrix
├── 14_backtracking
├── 15_dynamic_programming
└── README.md
Each folder includes practice problems with links and short explanations (WIP for some).
Here's a sample. Full list is in each folder.
- LC 303 – Range Sum Query: Immutable
- LC 525 – Contiguous Array
- LC 560 – Subarray Sum Equals K
- LC 167 – Two Sum II
- LC 15 – 3Sum
- LC 11 – Container With Most Water
- LC 643 – Max Average Subarray I
- LC 3 – Longest Substring Without Repeating Characters
- LC 76 – Minimum Window Substring
- LC 141 – Linked List Cycle
- LC 202 – Happy Number
- LC 287 – Find the Duplicate Number
- LC 206 – Reverse Linked List
- LC 92 – Reverse Linked List II
- LC 24 – Swap Nodes in Pairs
- LC 496 – Next Greater Element I
- LC 739 – Daily Temperatures
- LC 84 – Largest Rectangle in Histogram
- LC 215 – Kth Largest Element in an Array
- LC 347 – Top K Frequent Elements
- LC 373 – Find K Pairs with Smallest Sums
- LC 56 – Merge Intervals
- LC 57 – Insert Interval
- LC 435 – Non-overlapping Intervals
- LC 33 – Search in Rotated Sorted Array
- LC 153 – Find Minimum in Rotated Sorted Array
- LC 240 – Search a 2D Matrix II
- LC 257 – Binary Tree Paths
- LC 230 – Kth Smallest Element in a BST
- LC 124 – Binary Tree Maximum Path Sum
- LC 107 – Level Order Traversal II
- LC 133 – Clone Graph
- LC 113 – Path Sum II
- LC 210 – Course Schedule II
- LC 102 – Binary Tree Level Order Traversal
- LC 994 – Rotting Oranges
- LC 127 – Word Ladder
- LC 733 – Flood Fill
- LC 200 – Number of Islands
- LC 130 – Surrounded Regions
- LC 46 – Permutations
- LC 78 – Subsets
- LC 51 – N-Queens
- LC 70 – Climbing Stairs
- LC 322 – Coin Change
- LC 300 – Longest Increasing Subsequence
- LC 416 – Partition Equal Subset Sum
- LC 312 – Burst Balloons
- LC 1143 – Longest Common Subsequence
These are mix-type problems or just slightly harder, but they strengthen your understanding:
- LC 23 – Merge K Sorted Lists (Heap + Linked List)
- LC 138 – Copy List with Random Pointer (HashMap + Linked List)
- LC 329 – Longest Increasing Path in Matrix (DFS + Memoization)
- LC 212 – Word Search II (Trie + Backtracking)
Found a bug, want to add more problems, or have suggestions?
Open an issue or a pull request — happy to improve this together!
Please give this repo a star ⭐ — it helps others find it and motivates me to keep building and updating this resource.
“Consistency beats cramming. One pattern a day keeps rejection away.” 🚀