Today’s challenge requires us to understand why a coprocessor is working so hard to perform an apparently simple calculation.

→ Full code on GitHub

!!! commentary Today’s problem is based on an assembly-like language very similar to day 18, so I went back and adapted my code from that, which works well for the first part. I’ve also incorporated some advice from /r/haskell, and cleaned up all warnings shown by the -Wall compiler flag and the hlint tool.

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Sunday 24 December 2017 Jez Cope Technology Learning Advent of Code Haskell

Today’s challenge has us helping to clean up (or spread, I can’t really tell) an infection of the “sporifica” virus.

→ Full code on GitHub

!!! commentary I thought I’d have another play with Rust, as its Haskell-like features resonate with me at the moment. I struggled quite a lot with the Rust concepts of ownership and borrowing, and this is a cleaned-up version of the code based on some good advice from the folks on /r/rust.

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Sunday 24 December 2017 Jez Cope Technology Learning Advent of Code Rust

Today’s challenge asks us to assist an artist building fractal patterns from a rulebook.

→ Full code on GitHub

!!! commentary Another fairly straightforward algorithm: the really tricky part was breaking the pattern up into chunks and rejoining it again. I could probably have done that more efficiently, and would have needed to if I had to go for a few more iterations and the grid grows with every iteration and gets big fast.

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Sunday 24 December 2017 Jez Cope Technology Learning Advent of Code Python

Today’s challenge finds us simulating the movements of particles in space.

→ Full code on GitHub

!!! commentary Back to Python for this one, another relatively straightforward simulation, although it’s easier to calculate the answer to part 1 than to simulate.

import fileinput as fi
import numpy as np
import re

First we parse the input into 3 2D arrays: using numpy enables us to do efficient arithmetic across the whole set of particles in one go.

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Sunday 24 December 2017 Jez Cope Technology Learning Advent of Code Python

Today’s challenge asks us to help a network packet find its way.

→ Full code on GitHub

!!! commentary Today’s challenge was fairly straightforward, following an ASCII art path, so I thought I’d give Rust another try. I’m a bit behind on the blog posts, so I’m presenting the code below without any further commentary. I’m not really convinced this is good idiomatic Rust, and it was interesting turning a set of strings into a 2D array of characters because there are both u8 (byte) and char types to deal with.

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Sunday 24 December 2017 Jez Cope Technology Learning Advent of Code Rust

Today’s challenge introduces a type of simplified assembly language that includes instructions for message-passing. First we have to simulate a single program (after humorously misinterpreting the snd and rcv instructions as “sound” and “recover”), but then we have to simulate two concurrent processes and the message passing between them.

→ Full code on GitHub

!!! commentary Well, I really learned a lot from this one! I wanted to get to grips with more complex stuff in Haskell and this challenge seemed like an excellent opportunity to figure out a) parsing with the parsec library and b) using the State monad to keep the state of the simulator.

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Sunday 24 December 2017 Jez Cope Technology Learning Advent of Code Haskell

In today’s challenge we deal with a monstrous whirlwind of a program, eating up CPU and memory in equal measure.

→ Full code on GitHub (and Python driver script)

!!! commentary One of the things I wanted from AoC was an opportunity to try out some popular languages that I don’t currently know, including the memory-safe, strongly-typed compiled languages Go and Rust. Realistically though, I’m likely to continue doing most of my programming in Python, and use one of these other languages when it has better tools or I need the extra speed.

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Sunday 17 December 2017 Jez Cope Technology Learning Advent of Code Rust Python

Today’s challenge rather appeals to me as a folk dancer, because it describes a set of instructions for a dance and asks us to work out the positions of the dancing programs after each run through the dance.

→ Full code on GitHub

!!! commentary So, part 1 is pretty straight forward: parse the set of instructions, interpret them and keep track of the dancer positions as you go. One time through the dance. However, part 2 asks for the positions after 1 billion (yes, that’s 1,000,000,000) times through the dance. In hindsight I should have immediately become suspicious, but I thought I’d at least try the brute force approach first because it was simpler to code.

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Saturday 16 December 2017 Jez Cope Technology Learning Advent of Code Julia

Today’s challenge introduces two pseudo-random number generators which are trying to agree on a series of numbers. We play the part of the “judge”, counting the number of times their numbers agree in the lowest 16 bits.

→ Full code on GitHub

Ever since I used Go to solve day 3, I’ve had a hankering to try the other new kid on the memory-safe compiled language block, Rust. I found it a bit intimidating at first because the syntax wasn’t as close to the C/C++ I’m familiar with and there are quite a few concepts unique to Rust, like the use of traits. But I figured it out, so I can tick another language of my to-try list.

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Friday 15 December 2017 Jez Cope Technology Learning Advent of Code Rust

Today’s challenge has us helping a disk defragmentation program by identifying contiguous regions of used sectors on a 2D disk.

→ Full code on GitHub

!!! commentary Wow, today’s challenge had a pretty steep learning curve. Day 14 was the first to directly reuse code from a previous day: the “knot hash” from day 10. I solved day 10 in Haskell, so I thought it would be easier to stick with Haskell for today as well. The first part was straightforward, but the second was pretty mind-bending in a pure functional language!

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Friday 15 December 2017 Jez Cope Technology Learning Advent of Code Haskell