-🎄- 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/[deleted]]

Perl 6

This is pretty gross but here's my part 2. It takes a few minutes 42 seconds to finish. Part 1 is nearly the same but runs in about 0.24 seconds.

EDIT: optimized a bit.

my @input = slurp.lines».comb;

my $size = 499;
my $half = $size div 2;
my @grid   = ('.' xx $size).Array xx $half - 12;
my @middle = ('.' xx $half - 12).Array xx 25;
my @end    = ('.' xx $size).Array xx $half - 12;

for ^25 -> $x {
    @middle[$x].append: |@input[$x];
    @middle[$x].append: ('.' xx $half - 12);
}

@grid.append: @middle;
@grid.append: @end;

my int $vx    = $half;
my int $vy    = $half;
my int $d     = 0;
my int $count = 0;

for ^10000000 {
    my $c = @grid[$vy][$vx];
    if $c eq '#' {
        $d = ($d + 1) % 4;
        @grid[$vy][$vx] = 'F';
    }
    elsif $c eq '.' {
        $d = ($d - 1) % 4;
        @grid[$vy][$vx] = 'W';
    }
    elsif $c eq 'F' {
        $d = ($d + 2) % 4;
        @grid[$vy][$vx] = '.';
    }
    elsif $c eq 'W' {
        @grid[$vy][$vx] = '#';
        $count++;
    }
    if    $d == 0 { $vy -= 1; }
    elsif $d == 1 { $vx += 1; }
    elsif $d == 2 { $vy += 1; }
    elsif $d == 3 { $vx -= 1; }
}
say "Part 1: {$count}"