DSA Problem Solver

A clean, efficient environment for solving DSA problems with comprehensive testing.

🚀 Quick Start

1. Copy the template:

   cp problems/template/solution.cpp problems/your_problem_name/solution.cpp

2. Edit the solution:

   • Implement your solution in the Solution class
   • Update test cases in main()
   • Add problem description in the header comment

3. Compile and run:

   cd problems/your_problem_name
   g++ -std=c++17 -o solution solution.cpp
   .\solution

🛠️ Project Structure

DSA/
├── problems/                    # All problem solutions
│   ├── template/               # Problem template
│   │   ├── solution.cpp        # Solution template with test framework
│   │   ├── input.txt           # Sample input file
│   │   └── output.txt          # Expected output
│   └── second_largest/         # Example problem
│       └── solution.cpp        # Implemented solution
└── README.md                   # This file

📋 Features

• Comprehensive Testing Framework

  • Easy-to-add test cases
  • Detailed test output
  • Support for different input types

• Flexible Input

  • Manual input mode
  • File input support
  • Predefined test cases

• Documentation

  • Problem description template
  • Time/Space complexity analysis
  • Key insights section

🧪 Testing Your Solution

1. Using Predefined Tests:

   • Add test cases in main()
   • Run with: g++ -std=c++17 -o solution solution.cpp && .\solution

2. Manual Testing:

   • Uncomment manualTest() in main()
   • Run and enter custom input

3. File Input:

   • Uncomment #define LOCAL_TEST
   • Add test cases to input.txt
   • Run the program

📝 Adding a New Problem

1. Create a new directory:

   mkdir problems/your_problem_name
   cd problems/your_problem_name

2. Copy the template:

   cp ../template/solution.cpp .

3. Start solving!

🛠️ Setup Instructions

1. Prerequisites

   • C++ compiler (g++, clang, or MSVC)
   • C++11 or later

2. Getting Started

   • Clone this repository
   • Navigate to the project directory
   • Compile and run the example:

     cd problems
     g++ -std=c++11 second_largest.cpp -o second_largest
     .\second_largest

🧩 Creating a New Problem

1. Copy the Template

   cp problems/template.cpp problems/your_problem.cpp

2. Implement Your Solution

   • For class-based solutions (recommended for most platforms):

     class Solution {
     public:
         // Your solution method
         int solve(vector<int>& nums) {
             // Your code here
         }
     };

   • For function-based solutions:

     int solve(vector<int>& nums) {
         // Your code here
     }

🧪 Testing Your Solution

1. Using the Built-in Test Cases

   • The template includes a main() function with test cases
   • Add your test cases in the main() function
   • Example:

     int main() {
         Solution sol;
         
         // Test case 1
         vector<int> test1 = {1, 2, 3, 4};
         cout << "Test 1: " << sol.solve(test1) << endl;
         
         // Test case 2
         vector<int> test2 = {5, 5, 5};
         cout << "Test 2: " << sol.solve(test2) << endl;
         
         return 0;
     }

2. Running the Tests

   # Compile
   g++ -std=c++11 your_problem.cpp -o solution
   
   # Run
   .\solution

⚡ I/O Helpers

The template provides these helper methods:

// Reading input
int x = readInt();                    // Read a single integer
long long y = readLong();            // Read a 64-bit integer
string s = readString();             // Read a string (space/newline separated)
vector<int> arr = readIntArray();    // Read N followed by N integers
vector<vector<int>> mat = read2DIntArray();  // Read rows, cols, then rows*cols integers

// Writing output
printArray({1, 2, 3});  // Prints: 1 2 3
print2DArray({{1,2}, {3,4}});  // Prints: 1 2\n3 4

📝 Best Practices

1. Problem Documentation

   • Always include the problem statement at the top of your file
   • Document input/output format
   • Include constraints and examples

2. Code Style

   • Use meaningful variable names
   • Add comments for complex logic
   • Keep functions small and focused

3. Testing

   • Test edge cases (empty input, single element, etc.)
   • Test with maximum input sizes
   • Verify time and space complexity

🎯 Example: Second Largest Element

See problems/second_largest.cpp for a complete example solution that finds the second largest distinct element in an array.

🤝 Contributing

Feel free to contribute by adding more problems or improving the template. Make sure to follow the existing code style and include appropriate test cases.

3. Testing
   • Test edge cases (empty input, large inputs, etc.)
   • Use the sample test cases from the problem statement

🚀 Performance Tips

• Use \n instead of endl for faster output
• Prefer vector over arrays
• Use unordered_map when order doesn't matter
• Reserve vector capacity when size is known in advance

🤝 Contributing

1. Fork the repository
2. Create a new branch for your feature
3. Commit your changes
4. Push to the branch
5. Create a new Pull Request

📜 License

This project is open source and available under the MIT License.

🙏 Acknowledgments

• Standard Template Library (STL) documentation
• Competitive Programming resources