advent-of-code/2022/src/day_03.rs

type Data = Vec<String>;

fn get_priority(c: char) -> i32 {
    match c {
        'a'..='z' => c as i32 - 'a' as i32 + 1,
        'A'..='Z' => c as i32 - 'A' as i32 + 27,
        _ => panic!("expected letter"),
    }
}
fn parse(input: &str) -> Data {
    input.lines().map(str::to_owned).collect()
}
fn part_one(data: Data) -> i32 {
    data.iter()
        .map(|s| {
            use std::collections::HashSet;
            let (left, right) = s.split_at(s.len() / 2);
            let right_set: HashSet<char> = right.chars().collect();
            get_priority(left.chars().find(|c| right_set.contains(c)).unwrap())
        })
        .sum()
}
fn part_two(data: Data) -> i32 {
    data.as_slice()
        .chunks(3)
        .map(|c| {
            use std::collections::HashSet;
            let second_set: HashSet<char> = c[1].chars().collect();
            let third_set: HashSet<char> = c[2].chars().collect();
            get_priority(
                c[0].chars()
                    .find(|c| second_set.contains(c) && third_set.contains(c))
                    .unwrap(),
            )
        })
        .sum()
}

advent_of_code_macro::generate_tests!(
    day 3,
    parse,
    part_one,
    part_two,
    sample tests [157, 70],
    star tests [7908, 2838]
);