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Advent of Code 2022

On this page, I’ll sum up daily my experience doing the Advent of Code 2022.

Day 1: Counting calories

That is the easy introduction day. Nothing much to say: Lists, doing sums. Then sorting, and picking 3 numbers.

    for line in lines {
        if line.is_empty() {
            current_cal = 0;
        } else {
            current_cal += line.parse::<i32>().expect("need a mumber");



I should refactor the sort & reverse calls. I’m pretty sure this could be a 1 liner…

Day 2: Paper, Scissors, Rock or Rock, Paper, Scissors or …

I was too lazy. I’ll be honest: I’ve written too much match in my solution. I should refactor the thing to do 0. But that was end of the week and I wanted to get a walk.

    let playtype = match a {
        Play::Rock => {
            match b {
                Play::Paper => Type::Loss,
                Play::Scissors => Type::Win,
                Play::Rock => Type::Draw,

Wah I’ve just seen this blog post with quite better parsing using try_from. I really should use those.

Day 3: Intersections

Today’s exercise was about doing intersections of sets. Well, rust happens to have a very nice collection type for this: HashSet. And it also happens that this HashSet type has an intersection function.

    while groups.len() > 0 {
        let inter = groups.pop().unwrap().intersection(&groups.pop().unwrap()).cloned().collect();
        let inter: HashSet<char> = groups.pop().unwrap().intersection(&inter).cloned().collect();

        for c in inter.iter() {
            score_part2 += badge_to_number(*c);

All other exercises are on my Github account.