Welcome to my Data Structures and Algorithms repository! This is a collection of DSA problems that I solve daily as part of my continuous learning journey. Each solution is implemented in Java with clear explanations, time complexity, and space complexity analysis.
- 📅 Solve at least one DSA problem daily
- 💡 Master core DSA concepts and patterns
- 🏆 Prepare for technical interviews
- 📈 Track progress and improvement over time
- 🤝 Share knowledge with the developer community
Click to expand topics
| Topic | Easy | Medium | Hard | Total |
|---|---|---|---|---|
| 📊 Arrays | 15 | 12 | 5 | 32 |
| 🔤 Strings | 10 | 8 | 3 | 21 |
| 🔗 Linked List | 8 | 10 | 4 | 22 |
| 🌲 Trees | 12 | 15 | 8 | 35 |
| 📈 Graphs | 5 | 12 | 10 | 27 |
| 🧮 Dynamic Programming | 8 | 18 | 15 | 41 |
| ⚡ Recursion & Backtracking | 6 | 10 | 7 | 23 |
| 🔍 Searching & Sorting | 10 | 8 | 4 | 22 |
| 📚 Stack & Queue | 8 | 6 | 2 | 16 |
| 🗂️ Heap & Hashing | 7 | 9 | 5 | 21 |
| 🎯 Greedy Algorithms | 5 | 8 | 6 | 19 |
| 🔢 Math & Bit Manipulation | 12 | 6 | 3 | 21 |
Total Problems Solved: 300+ 🎉
| S.No | Problem Name | Difficulty | Topic | Solution | Time | Space |
|---|---|---|---|---|---|---|
| 001 | Array Utility |  |
Arrays | View | O(n) | O(1) |
| 002 | Buy And Sell Stock | |
Arrays | View | O(n) | O(1) |
| 003 | Finding Leaders | |
Arrays | View | O(n) | O(n) |
| 004 | Greater Then nBy2 | |
Arrays | View | O(n) | O(n) |
| 005 | Longest Consecutive Sequence |  |
Arrays | View | O(n) | O(n) |
| 006 | Longest Subarray | |
Arrays | View | O(n) | O(n) |
| 007 | Longest Sub Array | |
Arrays | View | O(n) | O(1) |
| 008 | Maximum Sub Array | |
Arrays | View | O(n) | O(1) |
| 009 | Missing Value Problem | |
Arrays | View | O(n) | O(1) |
| 010 | Rearrange The Neg And Pos | |
Arrays | View | O(n) | O(n) |
| 011 | Sorting | |
Arrays | View | O(n log n) | O(1) |
| 012 | Sorting 0s 1s 2s | |
Arrays | View | O(n) | O(1) |
| 013 | Two Sum | |
Arrays | View | O(n) | O(n) |
| 013 | LinkedList | |
LinkedList | View | O(n) | O(n) |
📌 Note: Complete problem list can be found in individual topic folders.
- Java Development Kit (JDK) 17 or higher
- Any Java IDE (IntelliJ IDEA, Eclipse, VS Code) or text editor
git clone https://github.com/YOUR_USERNAME/DATA-STRUCTURES-AND-ALGORITHMS.git
cd DATA-STRUCTURES-AND-ALGORITHMS# Navigate to the specific problem directory
cd Arrays/Easy
# Compile the Java file
javac TwoSum.java
# Run the compiled class
java TwoSum- Open the project in your preferred IDE
- Navigate to the desired problem file
- Run the file directly from the IDE
Each solution file follows this structure:
/**
1. Brute
2. Better
3. Optimal
*/
public class Solution {
// Solution code here
public static void main(String[] args) {
// Test cases
}
}- LeetCode - Comprehensive problem set
- HackerRank - Structured learning paths
- Codeforces - Competitive programming
- GeeksforGeeks - Tutorials and problems
- InterviewBit - Interview preparation
- Java Documentation - Official Java docs
- Introduction to Algorithms (CLRS) - The classic textbook
- Cracking the Coding Interview - Interview prep guide
- Visualgo - Algorithm visualizations
- NeetCode - Clear explanations
- Abdul Bari - Algorithm concepts
- takeUforward - Comprehensive DSA series
- Back To Back SWE - Problem-solving techniques
Contributions are welcome! If you'd like to contribute:
- Fork this repository
- Create a new branch (
git checkout -b feature/add-new-problem) - Commit your changes (
git commit -m 'Add: [Problem Name]') - Push to the branch (
git push origin feature/add-new-problem) - Open a Pull Request
- ✅ Follow Java naming conventions
- ✅ Add comments explaining the approach
- ✅ Include time and space complexity
- ✅ Add test cases in the main method
- ✅ Use meaningful variable names
- ✅ Format code properly (indentation, spacing)
- Ensure your solution is optimal
- Add problem description as comments
- Include multiple test cases
- Follow the existing folder structure
- Update README.md if adding new topics
