DSA fundamentals

A refined and expanded list of DSA topics, with high-quality problems and resources:

1. Arrays and Strings
   • Problems: • Two Sum • Container With Most Water • Longest Substring Without Repeating Characters • Trapping Rain Water • Longest Palindromic Substring
   • Resources: • Algorithms: Arrays and Strings (Stanford) • LeetCode Array Card
2. Linked Lists
   • Problems: • Reverse Linked List • Merge K Sorted Lists • LRU Cache • Copy List with Random Pointer • Find the Intersection point of Y LinkedList
   • Resources: • Linked List Problems (GeeksforGeeks) • Visualizing Linked Lists (UBC)
3. Stacks and Queues
   • Problems: • Valid Parentheses • Implement Queue using Stacks • Min Stack • Largest Rectangle in Histogram • Sliding Window Maximum • Design a Data Structure that Supports Both Stacks and Queues
   • Resources: • Stack and Queue Visualizations (USFCA) • Queue Reconstruction by Height (LeetCode)
4. Trees and Binary Search Trees
   • Problems: • Lowest Common Ancestor of a Binary Tree • Serialize and Deserialize Binary Tree • Binary Tree Maximum Path Sum • Construct Binary Tree from Preorder and Inorder Traversal • Validate Binary Search Tree • Diameter of Binary Tree • Binary Tree Right Side View
   • Resources: • Binary Trees (MIT OpenCourseWare) • Tree Traversal Techniques (TowardsDataScience)
5. Graphs
   • Problems: • Course Schedule (Topological Sort) • Word Ladder • Number of Islands • Alien Dictionary • Network Delay Time (Dijkstra’s Algorithm) • - Shortest Path in Binary Matrix • Find Eventual Safe States
   • Resources: • Graph Algorithms (Princeton) • Graph Theory Playlist (William Fiset)
6. Hash Tables
   • Problems: • Group Anagrams • Longest Consecutive Sequence • Subarray Sum Equals K • Design Twitter • Implement LRU Cache • four sum • Minimum Window Substring
   • Resources: • Hashing in C++ (GeeksforGeeks) • Hash Table Problems (InterviewBit)
7. Heaps and Priority Queues
   • Problems: • Merge K Sorted Lists • Find Median from Data Stream • Top K Frequent Elements • Minimum Cost to Connect Sticks • Swim in Rising Water • Reorganize String • Sliding window median
   • Resources: • Priority Queues (Princeton) • Heaps and Priority Queues (HackerEarth)
8. Dynamic Programming
   • Problems: • Longest Common Subsequence • Edit Distance • Coin Change • Longest Increasing Subsequence • Regular Expression Matching • Maximum Subarray • Decode ways • House robber
   • Resources: • Dynamic Programming (TopCoder) • Errichto’s DP lectures
9. Sorting and Searching
   • Problems: • Kth Largest Element in an Array • Search in Rotated Sorted Array • Median of Two Sorted Arrays • Find First and Last Position of Element in Sorted Array • Count of Smaller Numbers After Self • peak element • search a 2d matrix
   • Resources: • Sorting Algorithms Animations • Binary Search 101 (Topcoder)
10. Greedy Algorithms
    • Problems: • Jump Game • Task Scheduler • Gas Station • Partition Labels • Minimum Number of Arrows to Burst Balloons • Candy • Lemonade Change
    • Resources: • Greedy Algorithms (GeeksforGeeks) • Greedy Method (NPTEL)
11. Bit Manipulation
    • Problems: • Single Number • Counting Bits • Reverse Bits • Sum of Two Integers • UTF-8 Validation • Maximum Product of word lenghts • Bitwise AND of numbers range
    • Resources: • Bit Manipulation (HackerEarth) • Bit Twiddling Hacks
12. Trie
    • Problems: • Implement Trie (Prefix Tree) • Word Search II • Design Add and Search Words Data Structure • Maximum XOR of Two Numbers in an Array • Replace words • Concatenated Words
    • Resources: • Trie Data Structure (TopCoder) • Trie Visualization
13. Union Find (Disjoint Set)
    • Problems: • Number of Islands II • Accounts Merge • Redundant Connection • Satisfiability of Equality Equations • Graph Valid Tree • Longest Consecutive Sequence
    • Resources: • Disjoint Set Data Structures (GeeksforGeeks) • Union-Find Algorithm (Princeton)

General Resources:

1. CLRS Book - Comprehensive algorithm textbook
2. Algorithms Illuminated - Modern algorithm course and book series
3. Competitive Programmer’s Handbook - Comprehensive guide for competitive programming
4. CP-Algorithms - Detailed explanations of algorithms
5. VisuAlgo - Visualizing data structures and algorithms through animation

Practice Platforms:

1. LeetCode
2. Codeforces
3. AtCoder
4. HackerRank
5. CodeChef

This expanded list covers a wide range of topics and includes more challenging problems.