MyCSES - CSES Problem Set Solutions

This repository contains my solutions to problems from the CSES Problem Set, implemented in C++. The CSES Problem Set is a collection of competitive programming practice problems that cover various algorithmic topics.

👨‍💻 Author

Kunal Sharma
IIT Jammu

📁 Repository Structure

The solutions are organized by problem categories:

├── 1_introductory_problems/    # Basic algorithmic problems
├── 2_sorting_searching/        # Sorting and searching algorithms
├── 3_dp/                      # Dynamic programming problems
├── 7_mathematics/             # Mathematical problems
├── .builds/                   # Build configurations
└── .vscode/                   # VS Code settings

🧩 Problem Categories

1. Introductory Problems

• Two Sets - Partitioning numbers into two equal sum sets
• Gray Code - Generating Gray code sequences
• Apple Division - Minimizing difference in apple weight distribution
• Chessboard and Queens - N-Queens problem variant
• Coin Piles - Mathematical puzzle with coin removal rules
• Bit Strings - Counting binary strings

2. Sorting and Searching

• Apartments - Matching applicants to apartments
• Movie Festival - Activity selection problem
• Collecting Numbers - Array manipulation problems
• Minimum Coin Sum - Finding smallest unrepresentable sum

3. Dynamic Programming

• Minimizing Coins - Classic coin change problem

7. Mathematics

• Exponentiation 2 - Fast exponentiation with modular arithmetic
• Sum of Divisors - Mathematical series calculation
• Creating Strings - Combinatorics with factorial calculations

🔧 Implementation Details

Language & Standards

• Language: C++
• Compiler: Standard C++ compiler
• Libraries: STL (Standard Template Library)

Common Patterns Used

// Standard template used across solutions
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
#define mod 1000000007

// Fast I/O optimization
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);

Key Algorithmic Techniques

• Fast Exponentiation: Binary exponentiation for efficient power calculation
• Modular Arithmetic: Using MOD = 1000000007 for large number calculations
• Dynamic Programming: Bottom-up and memoization approaches
• Greedy Algorithms: Activity selection and optimization problems
• Bit Manipulation: Efficient subset generation and Gray codes
• Mathematical Formulas: Combinatorics and number theory

🚀 How to Use

1. Clone the repository:

   git clone https://github.com/ks-iitjmu/MyCSES.git
   cd MyCSES

2. Compile a solution:

   g++ -o solution category/problem_name.cpp

3. Run the solution:

   ./solution < input.txt

📊 Problem Solving Approach

Each solution follows a structured approach:

1. Problem Analysis: Understanding constraints and edge cases
2. Algorithm Selection: Choosing optimal time/space complexity approach
3. Implementation: Clean, readable C++ code
4. Optimization: Fast I/O and efficient algorithms for competitive programming

🏆 Competitive Programming Features

• Fast I/O: All solutions use optimized input/output
• Type Definitions: Consistent use of typedef long long ll
• Modular Arithmetic: Proper handling of large numbers
• Edge Case Handling: Robust solutions for boundary conditions
• Clean Code: Readable and well-structured implementations

📈 Progress Tracking

• ✅ Introductory Problems: Multiple problems solved
• ✅ Sorting and Searching: Core algorithms implemented
• ✅ Dynamic Programming: Foundation problems completed
• ✅ Mathematics: Advanced mathematical concepts covered

🔗 Useful Links

• CSES Problem Set
• CSES Book - Competitive Programming Handbook

📝 Notes

• Solutions are optimized for competitive programming contests
• Time complexity is prioritized for large input constraints
• Code follows standard competitive programming conventions
• All solutions have been tested against CSES judge system

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Feel free to explore the solutions and use them for learning purposes. Happy coding! 🚀