🚀 AlgoPrep: Mastering Data Structures & Algorithms in C#

Welcome to AlgoPrep, a curated C# repository focused on mastering data structures and algorithms through consistent problem-solving using LeetCode.

✨ Built for devs who want clarity, structure, and C#-specific practice for technical interviews or foundational mastery.

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📚 Repository Highlights

• 📦 Modular Problem Structure: Each problem lives in its own self-contained project
• 🧠 Pattern-Based Learning: Linked to algorithm patterns & LeetCode75 roadmap
• ⚙️ C# Focused: Clean, idiomatic .NET code with comments and optional complexity analysis
• ✅ Progress-Oriented: Easy to track and extend with your own study path

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🧱 Folder Structure

algoprep/
├── docs/                 # Docs, Custom Study Guides, Alogo Patterns
│   ├── linkedlists/      #Specific File to breadown patterns on Linked Lists
│   │   └── README.md
│   ├── CSharp_Algorithm_Patterns.md # Pattern explanations (e.g. Two Pointers, Sliding Window)
│   ├── 7_Day_Crash_Course.md   # Only 7 Days to prep? This study guide gives you a crash course to refresh your DSA skills
├── leetcode75/                 # LeetCode 75 Study Plan problems
├── Problems/                   # Individual problems
│   ├── 001_TwoSum/
│   │   └── 001_TwoSum.csproj
│   ├── 002_AddTwoNumbers/
│   │   └── 002_AddTwoNumbers.csproj
│   └── ...
├── algoprep.sln                # Solution file (includes all projects)
└── README.md                   # You're here!

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🔧 Getting Started

📦 Requirements

• .NET SDK
• IDE: Visual Studio or VS Code with C# extension

▶️ Run a Problem

cd Problems/001_TwoSum
dotnet run

🧪 (Optional) Add Unit Tests

You can create a Tests/ folder using xUnit or NUnit for TDD-style learning.

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Important Note About .NET Project Creation

When using dotnet new console -n ProblemName, the command does not automatically add the newly created project to your existing solution file (.sln).

Why This Happens

• Explicit Control: The .NET CLI is designed to give you explicit control. It assumes you might want to create projects independently of a solution or add them to a different solution later.

• Location: When you run dotnet new console -n ProblemName, it creates a new folder named ProblemName and puts the .csproj file inside it, along with the Program.cs and other project files. It doesn't automatically know where your solution file is located.

• Solution Files as Organizers: Solution files (.sln) are organizational tools that help IDEs and the dotnet CLI understand relationships between multiple projects. Projects can exist without being part of any solution.

Workflow for Adding New Problems

1. Create a New Project for the Problem

Navigate to your repository root and run:

dotnet new console -n ProblemName -o Problems/ProblemName

This creates:

• A new folder Problems/ProblemName
• A C# project file ProblemName.csproj inside that folder
• A default Program.cs file

2. Add the Project to Your Solution

After creating the project, you need to explicitly add it to your solution:

dotnet sln add Problems/ProblemName/ProblemName.csproj

3. Implement Your Solution

Now you can implement your solution in the Program.cs file or create additional classes as needed.

4. Build and Test

Build your solution:

dotnet build

Run your specific project:

dotnet run --project Problems/ProblemName/ProblemName.csproj

Complete Example Workflow

# Initial setup (only needed once)
mkdir InterviewPrep
cd InterviewPrep
dotnet new sln -n InterviewProblems

# For each new problem
dotnet new console -n TwoSumProblem -o Problems/TwoSumProblem
dotnet sln add Problems/TwoSumProblem/TwoSumProblem.csproj

# Navigate to problem directory to work on it
cd Problems/TwoSumProblem
# Edit Program.cs...

# Or run the project from the solution root
cd ../..
dotnet run --project Problems/TwoSumProblem/TwoSumProblem.csproj

IDE Integration

When you open InterviewProblems.sln in Visual Studio or VS Code (with C# extension), you'll see all problems listed in the Solution Explorer, making it easy to navigate between different problem implementations.

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📈 Study Plans

This repo includes structured learning plans:

✅ LeetCode 75 Plan

• Focused sequence of ~75 curated LeetCode problems.
• Learn by topic: Arrays, Hash Maps, Linked Lists, Trees, DP, etc.
• Annotated and explained in C# context.

🔁 C# Algorithm Patterns

• Strategy-focused guide across common patterns:
  • Two Pointers
  • Sliding Window
  • DFS/BFS
  • Dynamic Programming
  • Greedy
  • ...and more.

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🤝 Contributing

If you'd like to improve the repo or add new problems:

1. Fork the repo
2. Add your project in /Problems/###_ShortName/
3. Use C# and follow naming conventions
4. Submit a pull request

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🧠 Tips for Effective Learning

• Code from scratch after understanding solutions
• Comment key decisions and complexities
• Talk through your approach like a mock interview
• Track time spent and review failures intentionally

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“It’s not that I’m so smart, it’s just that I stay with problems longer.”
— Albert Einstein

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📬 Contact

Maintained by @gillisce
Feel free to open issues for questions, suggestions, or new patterns!

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Happy coding! 💻