Advent of Code 2024 - Day 3

link : https://adventofcode.com/2024/day/3

For this challenge, this regex site helped me a lot to extract what I needed from the input file.

Part One | Mull It Over

use std::{fs::File, io::{self, Read}};
use regex::Regex;

fn inputs_to_vec(str_inputs: &String) -> Vec<String> {
    let re = Regex::new(r"mul\([0-9]{1,3},[0-9]{1,3}\)").unwrap();
    let mut mult_array: Vec<String> = Vec::new();

    for extracted in re.captures_iter(&str_inputs) {
        mult_array.push((&extracted[0]).to_string());
    }

    mult_array
}

fn get_value_one(str_inputs: &String) -> Vec<String> {
    let re = Regex::new(r"do\(\)|don\'t\(\)|mul\([0-9]{1,3},[0-9]{1,3}\)").unwrap();
    let mut instructions: Vec<String> = Vec::new();

    for instruction in re.captures_iter(&str_inputs) {
        instructions.push((&instruction[0]).to_string());
    }

    instructions

}

fn main() -> io::Result<()> {
    let mut file = File::open("input_2.txt")?;
    let mut str_inputs = String::new();
    let mut mult_array: Vec<String>;
    let result: i32 = 0;

    file.read_to_string(&mut str_inputs)?;
    mult_array = inputs_to_vec(&str_inputs);
    for mult in mult_array {
        let value: Vec<i32>;
        value = get_value_two(&mult);
        result += value[0] * value[1];
    }

    println!("PART 1 : {}", result);

    Ok(())
}

Part Two

use std::{fs::File, io::{self, Read}};
use regex::Regex;

fn inputs_to_vec(str_inputs: &String) -> Vec<String> {
    let re = Regex::new(r"mul\([0-9]{1,3},[0-9]{1,3}\)").unwrap();
    let mut mult_array: Vec<String> = Vec::new();

    for extracted in re.captures_iter(&str_inputs) {
        mult_array.push((&extracted[0]).to_string());
    }

    mult_array
}

fn get_value_two(mult: &String) -> Vec<i32>{
    let re = Regex::new(r"[0-9]{1,3}").unwrap();
    let mut value: Vec<i32> = Vec::new();

    for str_num in re.captures_iter(&mult){
        value.push((&str_num[0]).parse().unwrap());
    }

    value
}

fn main() -> io::Result<()> {
    let mut file = File::open("input_2.txt")?;
    let mut str_inputs = String::new();
    let mut mult_array: Vec<String>;
    let result: i32 = 0;
    let mut activated: bool = true;

    file.read_to_string(&mut str_inputs)?;
    mult_array = get_value_one(&str_inputs);
    for element in &mult_array {
        let value: Vec<i32>;
        if element.contains("mul(") {
            if activated {
                value = get_value_two(&element);
                result += value[0] * value[1];
            }
        } else if element.contains("do(") {
            activated = true;
        } else if element.contains("don\'t(") {
            activated = false;
        }
    }

    println!("PART 2 : {}", result);

    Ok(())
}