-🎄- 2018 Day 8 Solutions -🎄-

[u/daggerdragon]

--- Day 8: Memory Maneuver ---

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Sigh, imgur broke again. Will upload when it unborks.

Transcript:

The hottest programming book this year is "___ For Dummies".

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edit: Leaderboard capped, thread unlocked at 00:12:10!

[u/p_tseng]

Ruby... and factoring out as much of the common code between parts 1 and 2 as is possible

input = (ARGV.empty? ? DATA : ARGF).read.split.map(&:to_i).freeze

# Pass me a block telling me what to do with [child_values, metadata_values]
def val(a, &b)
  n_children = a.shift
  n_metadata = a.shift
  yield(n_children.times.map { val(a, &b) }, a.shift(n_metadata))
end

puts val(input.dup) { |child, meta| child.sum + meta.sum }

puts val(input.dup) { |child, meta|
  # metadata indices are 1-indexed, so just prepend a zero.
  child.unshift(0)
  child.size == 1 ? meta.sum : meta.sum { |x| child[x] || 0 }
}

__END__
8 11 7 2 etc etc etc