Today I am joining you from the relative discomfort of my living room (since my better half has commandeered the home office due to Way Too Many Calls) to tackle the day 6 challenge, which I’m excited about: maybe despite, maybe because of, the low-grade fever I’m under.

Part 1

Our input is a jumble of letters, and we’re supposed to find the position of the first substring that’s “four different characters”.

Part 1

The day 5 challenge actually looks fun!

Our input looks like this:

[D] [N] [C] [Z] [M] [P] 1 2 3 move 1 from 2 to 1 move 3 from 1 to 3 move 2 from 2 to 1 move 1 from 1 to 2

Which is a visual representation of stacks, and so, for once, we have some serious parsing to do, and that means I finally have a good reason to bust out the nom crate.

Part 1

Let’s tackle the day 4 challenge!

In this one, we get an input like this:

2-4,6-8 2-3,4-5 5-7,7-9 2-8,3-7 6-6,4-6 2-6,4-8

Each line has two ranges: the first line has ranges containing 2, 3, 4, and 6, 7, 8. We must count how many pairs have ranges where one fully contains the other.

In Rust, we can express this with “inclusive ranges” (std::ops::RangeInclusive), and those implement Iterator, so we can do:

Part 1

I’m not sure where the day 3 challenge is going, because the problem statement for the first part is kinda convoluted.

As usual we have an input, like this:

vJrwpWtwJgWrhcsFMMfFFhFp jqHRNqRjqzjGDLGLrsFMfFZSrLrFZsSL PmmdzqPrVvPwwTWBwg wMqvLMZHhHMvwLHjbvcjnnSBnvTQFn ttgJtRGJQctTZtZT CrZsJsPPZsGzwwsLwLmpwMDw

Each line represents the contents of a “rucksack”, divided in two halves (which are called “compartments”), so for line 1:

Part 1

In the day 2 challenge, we’re playing Rock Papers Scissors.

We’re given a strategy guide like so:

A Y B X C Z

Left column is “their move”: A means Rock, B means Paper, C means Scissors. Right column is “our move”: X means Rock, Y means Paper, Z means Scissors.

Each line corresponds to a turn, and we must calculate the total score we get. Picking “Rock” gives 1 point, “Paper” gives 2 points, and “Scissors” gives 3. Losing the round gives 0 points, drawing gives 3, winning it gives 6.

Two years ago, I did part of Advent of Code 2020 using the Rust language. It was a lot of fun, so let’s try it again!

The problem statement

Our input looks something like this:

1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

Each group of lines separated by an empty line is a list of food items an elf is carrying: each line corresponds to the number of calories in that food.

Let’s use the Advent of Code 2022, a series of programming challenges of increasing difficulty, to learn more about the Rust programming language.

async_trait’s one weird type ascription trick

Now that I got the Log in with GitHub feature working, let’s explore what this would’ve looked like with the async_trait crate.

First up, the trait definition:

/// Something that can refresh credentials #[async_trait::async_trait] pub trait CredentialsRefresher { async fn refresh(&self, creds: &FutileCredentials) -> eyre::Result<FutileCredentials>; }