01.rs

advent_of_code::solution!(1);

pub fn part_one(input: &str) -> Option<u32> {
    let result = input
        .lines()
        .filter_map(|lll| {
            let first = lll.chars().find(char::is_ascii_digit);
            let second = lll.chars().rfind(char::is_ascii_digit);
            Some(first?.to_digit(10)? * 10 + second?.to_digit(10)?)
        })
        .sum();

    Some(result)
}

pub fn part_two(input: &str) -> Option<u32> {
    let result = input
        .lines()
        .filter(|line| !line.is_empty())
        .map(|line| {
            line.to_string()
                .replace("one", "one1one")
                .replace("two", "two2two")
                .replace("three", "three3three")
                .replace("four", "four4four")
                .replace("five", "five5five")
                .replace("six", "six6six")
                .replace("seven", "seven7seven")
                .replace("eight", "eight8eight")
                .replace("nine", "nine9nine")
        })
        .map(|line| {
            line.chars()
                .filter_map(|c| c.to_digit(10))
                .collect::<Vec<u32>>()
        })
        .map(|vec| 10 * vec.first().unwrap() + vec.last().unwrap())
        .sum();

    Some(result)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_part_one() {
        let result = part_one(&advent_of_code::template::read_file_part(
            "examples", DAY, 1,
        ));
        assert_eq!(result, Some(142u32));
    }

    #[test]
    fn test_part_two() {
        let result = part_two(&advent_of_code::template::read_file_part(
            "examples", DAY, 2,
        ));
        assert_eq!(result, Some(281));
    }
}