2017

Advent of Code 2017

Spoiler Warning: If you want to solve the challenges by yourself, don't read the code.

This directory contains the code I used to solve the challenges from Advent of Code 2017.

Contents

The following table lists the available solutions by day and language. I also added a short summary for each day. I marked the solutions which I consider especially valuable or pretty with a star (☆).

Day	Scala	Rust	Description
01	x		Sum equal digits
02	x		Sum spreadsheet min/max
03	x		Ulam spiral fibonacci mashup
04	x		Anagram passphrases
05	x		Weird jump instructions
06	x		Memory loop debugger
07	x		Programs disc balance tree
08			I Heard You Like Registers
09	x		Garbage and groups stream counting
10	x		Knot hash
11	x		Hex grid distances
12	x		Connected components
13	x		Modulus stuff like disks last year
14	x		Grid of knot hash and connected components
15	x		Generating number list with bitmasks
16	x		Letter permutation program dance
17	x		Cyclic list intertion tracking
18			Some Intcode stuff?
19	x		Walking the line
20	x		Particles
21			Binary pattern expansion
22	x		Virus grid moving
23			Some Intcode stuff?
24	x		Bulding bridges with values and lengths
25	x		Turing machine
Σ	21	0

Takeaways

• Scala generally feels like a more sane version of Java, especially if you do functional things.
• Scala has really confusing syntax, e.g. .filter(_.length == 1) works, but .filter(foo(_).length == 1) doesn't (the underscore can be many things)
• Scala generally feels like a more ugly version of Haskell, especially if you do functional things.
• For example Some(3).getOrElse(recursion(...)) will not work, because it ain't lazy

Other solutions

I enjoy looking at how other coders solved the riddles to learn even more. This year I follow (A-Z):

• cschell (Python, Ruby, Rust)
• fdlk (Scala)
• glguy (Haskell)
• msullivan (Haskell, Python)

These coders form last year didn't yet push anything this year, but I'll keep an eye open (A-Z):

• bildzeitung (Python?)
• Pyrobolser (C#)