Advent of Code (AoC) Solutions in Rust

This repository contains my solutions for Advent of Code, structured as a single Cargo project.

You can run any solution by passing the year, day, and an optional mode (test or final/input):

cargo run -- <year> <day> [mode]

• <year>: The 4-digit year (e.g., 2015, 2024)
• <day>: The day number (e.g., 1 for day 1, 25 for day 25)
• [mode]: (Optional) The name of the input file to run against, without the .txt extension. Defaults to test. Common modes are test and final (or input).

Examples:

# Runs year 2015, day 1 using test.txt
cargo run -- 2015 1 

# Runs year 2015, day 1 using test.txt
cargo run -- 2015 1 test 

# Runs year 2015, day 1 using final.txt (or input.txt)
cargo run -- 2015 1 final 

To add a solution for a new day in a year that already exists (e.g., Day 12 of 2015):

1. Create the Day Directory: Navigate to the specific year's folder (src/aoc_YYYY) and create a new folder named dayXX (padded with a leading zero, e.g., day12).
2. Create Required Files: Inside the dayXX folder, create:
   • mod.rs
   • test.txt (for example inputs)
   • final.txt or input.txt (for the real puzzle input)
3. Implement the Solution: In dayXX/mod.rs, write your solution logic. It must expose a run(file_path: &str) function:

   use std::fs;
   
   pub fn run(file_path: &str) {
       let contents = fs::read_to_string(file_path).expect("File not found");
       
       // Add your solution logic here
   
       println!("Part 1 Answer:");
       println!("Part 2 Answer:");
   }

4. Register the Day: Open the year's module file (e.g., src/aoc_YYYY/mod.rs) and do two things:
   • Declare the module at the top: pub mod dayXX;
   • Add it to the run method's match statement:

     "XX" => dayXX::run(path),

     (Make sure to match the padded string, e.g., "12", "09")

To add the first solution for an entirely new year (e.g., 2025):

1. Create the Year Directory: Under src/, create a new directory named aoc_YYYY (e.g., aoc_2025).
2. Create the Year Module: Give this directory a mod.rs file (src/aoc_YYYY/mod.rs). Set it up to route days:

   pub mod day01;
   
   pub fn run(day: &str, path: &str) {
       match day {
           "01" => day01::run(path),
           _ => println!("waiting for the solution"),
       }
   }

3. Create the First Day: Inside the new aoc_YYYY directory, create a day01 folder and follow the steps from "Adding a New Solution for an Existing Year" to add mod.rs, test.txt, etc.
4. Register the Year: Open src/main.rs:
   • Declare the new year module at the top of the file: mod aoc_YYYY;
   • Update the match year.as_str() block inside the main function to route to your new year:

     "YYYY" => aoc_YYYY::run(&day_padded, &file_path),