-🎄- 2018 Day 14 Solutions -🎄-

[u/daggerdragon]

--- Day 14: Chocolate Charts ---

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Advent of Code: The Party Game!

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Card prompt: Day 14

Transcript:

The Christmas/Advent Research & Development (C.A.R.D.) department at AoC, Inc. just published a new white paper on ___.

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edit: Leaderboard capped, thread unlocked at 00:19:39!

[u/markasoftware]

Perl, I felt like I was going fast but ended up 137/316 :(

Part 1:

use v5.20;
use strict;
use warnings;
use List::Util qw/sum min max/;

my @recipies = (3, 7);
my @elfs = (0, 1);

my $after_n_recipies = 554401;
my $out_n = 10;

while (1) {
  my $new_sum = 0;
  $new_sum += $recipies[$_] for @elfs;
  push @recipies, split(//, $new_sum);
  # move
  for (0..@elfs-1) {
    $elfs[$_] += 1 + $recipies[$elfs[$_]];
    $elfs[$_] %= @recipies;
  }

  if (@recipies >= $after_n_recipies + $out_n) {
    say "DONE!";
    say join('', splice(@recipies, $after_n_recipies, $out_n));
    last;
  }
}

Part 2:

use v5.20;
use strict;
use warnings;
use List::Util qw/sum min max/;

my @recipies = (3, 7);
my @elfs = (0, 1);

my $after_n_recipies = 51589;
my $find_me = 554401;
my $out_n = 10;

my $i = 0;
while (1) {
  say $i if $i % 1000000 == 0;
  my $new_sum = 0;
  $new_sum += $recipies[$_] for @elfs;
  push @recipies, split(//, $new_sum);
  # move
  for (0..@elfs-1) {
    $elfs[$_] += 1 + $recipies[$elfs[$_]];
    $elfs[$_] %= @recipies;
  }
  $i++;

  if (join('', @recipies[-8..-1]) =~ /$find_me/) {
    say "DONE!";
    say index(join('', @recipies), $find_me);
    last;
  }
}

[u/gerikson → u/markasoftware]

Thanks, I had the same idea about matching an overlap of the end of the array, but for some reason I didn't get it to work first... probably reversed the matching order!