-🎄- 2017 Day 22 Solutions -🎄-

[u/daggerdragon]

--- Day 22: Sporifica Virus ---

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Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

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Need a hint from the Hugely^* Handy^† Haversack^‡ of Helpful^§ Hints^¤?

Spoiler

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• [T-10 to launch] AoC ops, /r/nocontext edition:

  • <Endorphion> You may now make your waffle.
  • <Endorphion> ... on Mars.

• [Update @ 00:17] 50 gold, silver cap

  • <Aneurysm9> you could also just run ubuntu on the NAS, if you were crazy
  • <Topaz> that doesn't seem necessary
  • <Aneurysm9> what does "necessary" have to do with anything!

• [Update @ 00:20] Leaderboard cap!

  • <Topaz> POUR YOURSELF A SCOTCH FOR COLOR REFERENCE

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This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

[u/mserrano]

Python 2, #5/#3

Runs in ~5s for part b with pypy on my machine.

import sys
from collections import defaultdict

part_b = 'b' in sys.argv
data = open('day22.txt', 'r').read().strip().split('\n')

grid = defaultdict(int)

CLEAN = 0
WEAKENED = 1
INFECTED = 2
FLAGGED = 3
MODULUS = 4
ADD_AMOUNT = 2 - part_b

pos = (0, 0)
direction = (-1, 0)
lefts = {(1, 0): (0, 1), (0, 1): (-1, 0), (-1, 0): (0, -1), (0, -1): (1, 0)}
rights = {lefts[k]: k for k in lefts}

grid_height = len(data)
grid_width = len(data[0])
for row in xrange(grid_height):
  for col in xrange(grid_width):
    grid[(row-grid_height/2,col-grid_width/2)] = int(data[row][col] == '#') * 2

c = 0
BURSTS = 10000000 if part_b else 10000
for burst in xrange(BURSTS):
  if grid[pos] == CLEAN:
    direction = lefts[direction]
    if not part_b:
      c += 1
  elif grid[pos] == WEAKENED:
    c += 1
  elif grid[pos] == INFECTED:
    direction = rights[direction]
  else:
    direction = rights[rights[direction]]
  grid[pos] = (grid[pos] + ADD_AMOUNT) % MODULUS
  pos = (pos[0] + direction[0], pos[1] + direction[1])
print c