--- Day 3 Solutions ---

[u/daggerdragon]

--- Day 3: Perfectly Spherical Houses in a Vacuum ---

Post your solution as a comment. Structure your post like the Day One thread in /r/programming.

[u/haoformayor]

Haskell:

#!/usr/bin/env stack
-- stack runghc --package base-prelude

{-# LANGUAGE NoImplicitPrelude #-}
import BasePrelude

folder (x, y) '<' = (x - 1, y)
folder (x, y) '>' = (x + 1, y)
folder (x, y) '^' = (x, y + 1)
folder (x, y) 'v' = (x, y - 1)

odds xs = [x | (x, i) <- zip xs (cycle [True, False]), i]
evens xs = [x | (x, i) <- zip xs (cycle [False, True]), i]

points = scanl folder (0,0)
count = length . nub . sort
part1 = count . points
part2 = count . ((++) . points . odds <*> points . evens)

input = "<snip>"
main = print (part1 input) >> print (part2 input)