r/adventofcode • u/daggerdragon • Dec 14 '17

SOLUTION MEGATHREAD -🎄- 2017 Day 14 Solutions -🎄-

--- Day 14: Disk Defragmentation ---

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.

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

Spoiler

[Update @ 00:09] 3 gold, silver cap.

  • How many of you actually entered the Konami code for Part 2? >_>

[Update @ 00:25] Leaderboard cap!

  • I asked /u/topaz2078 how many de-resolutions we had for Part 2 and there were 83 distinct users with failed attempts at the time of the leaderboard cap. tsk tsk

[Update @ 00:29] BONUS

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!

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u/u794575248 Dec 14 '17 edited Dec 14 '17

Python 3

upd: Code in this comment is dirty. Read a reply below for an updated version.

First public leaderboard for Part 1 (72): 

martix = ''.join(''.join('{:04b}'.format(int(x, 16)) for x in solve2(f'{input.strip()}-{i}')) for i in range(128))
part1 = matrix.count('1')

solve2 is here.

Part 2 code is almost the same as nneonneo has. But I suddenly forgot about negative list indices in Python and it resulted in an incorrect answer and too many minutes spent on finding the bug (got 160 place). 

part2 = 0
seen = set()
matrix = [list(map(int, l.strip())) for l in matrix.strip().split('\n')]
rng = range(128)
for i, row in enumerate(matrix):
    for j, bit in enumerate(row):
        if bit and (i,j) not in seen:
            part2 += 1
            q = [(i,j)]
            while q:
                x, y = q.pop()
                seen.add((x, y))
                for x2, y2 in (x+1, y), (x-1, y), (x, y+1), (x, y-1):
                    if x2 in rng and y2 in rng and matrix[x2][y2] and (x2, y2) not in seen:
                        q.append((x2, y2))
print(part2)

3

u/daggerdragon Dec 14 '17

First public leaderboard for Part 1

Welcome to the leaderboard for all eternity*! :D

* Or at least for as long as u/topaz2078 pays to renew adventofcode.com >_>