adventofcode2024/day_07/src/main.rs

// https://adventofcode.com/2024/day/7
//
// Run command: cargo run ./input.txt

use std::{
    collections::HashSet,
    env,
    error::Error,
    fs::File,
    io::{BufReader, prelude::*},
};

fn create_operator_set_recurse(
    operators_permutation_set: &mut HashSet<Vec<bool>>,
    operators: Vec<bool>,
) {
    operators_permutation_set.insert(operators.clone());
    if !operators.contains(&false) {
        return;
    }

    for i in 0..operators.len() {
        if operators[i] {
            continue;
        }
        let mut new_operators = operators.clone();
        new_operators[i] = true;
        create_operator_set_recurse(operators_permutation_set, new_operators);
    }
}

fn create_operator_set(num_of_operators: usize) -> HashSet<Vec<bool>> {
    let mut operator_sets: HashSet<Vec<bool>> = HashSet::new();
    create_operator_set_recurse(&mut operator_sets, vec![false; num_of_operators]);
    operator_sets
}

#[derive(Debug, Clone, Copy)]
enum Ops {
    Multiply,
    Add,
}

#[derive(Debug)]
struct Equation {
    answer: i32,
    components: Vec<i32>,
}

impl Equation {
    fn new(equation_str: &str) -> Result<Equation, String> {
        let split_equation: Vec<_> = equation_str.split(":").collect();
        if split_equation.len() != 2 {
            return Err(format!("Invalid equation string: {}", equation_str));
        }
        let answer = match split_equation[0].parse() {
            Ok(a) => a,
            Err(_) => {
                return Err(format!(
                    "Error parsing answer {} in equation: {}",
                    split_equation[0], equation_str
                ));
            }
        };
        let components = split_equation[1]
            .split_whitespace()
            .map(|c| match c.parse::<i32>() {
                Ok(a) => Ok(a),
                Err(_) => Err(format!(
                    "Error parsing component {} in equation: {}",
                    c, equation_str
                )),
            })
            .collect::<Result<Vec<i32>, String>>()?;
        Ok(Equation { answer, components })
    }

    fn solvable(&self) -> bool {
        let op_combination: HashSet<HashSet<i32>> = HashSet::new();
        false
    }
}

fn main() -> Result<(), Box<dyn Error>> {
    // Handle command input
    let args: Vec<String> = env::args().collect();
    if args.len() != 2 {
        panic!(
            "{} must be run with a single argument of file name!",
            &args[0]
        )
    }
    let input_file = &args[1];

    let file = File::open(input_file)?;
    let buffer = BufReader::new(file);

    let mut equations = Vec::new();
    for line in buffer.lines() {
        let line = line?;
        equations.push(Equation::new(&line)?)
    }

    println!("{:?}", equations);

    let operator_set = create_operator_set(3);
    println!("{:?}", operator_set);

    Ok(())
}