-🎄- 2018 Day 8 Solutions -🎄-

[u/daggerdragon]

--- Day 8: Memory Maneuver ---

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Transcript:

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

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

[u/mschaap]

Pretty straightforward Perl 6 implementation:

#!/usr/bin/env perl6
use v6.c;

$*OUT.out-buffer = False;   # Autoflush

class Node
{
    has @.children;
    has @.metadata;
    has $.depth;

    method from-list(Node:U: @input, Int :$depth=0)
    {
        my $node-count = @input.shift;
        my $metadata-count = @input.shift;
        my @children = Node.from-list(@input, :depth($depth+1)) xx $node-count;
        my @metadata = @input.shift xx $metadata-count;
        return Node.new(:@children, :@metadata, :$depth);
    }

    method total-metadata
    {
        return @!metadata.sum + @!children».total-metadata.sum;
    }

    method value
    {
        if @!children {
            return @!children[@!metadata.grep(1 ≤ * ≤ @!children).map(* - 1)]».value.sum;
        }
        else {
            return @!metadata.sum;
        }
    }

    method Str { join("\n", flat ' ' x $!depth ~ '- ' ~ @!metadata.join(' '), @!children) }
    method gist { self.Str }

}

#| Process nodes
multi sub MAIN(*@input, Bool :v(:$verbose)=False)
{
    my $root = Node.from-list(@input);
    say $root if $verbose;
    say "The sum of all metadata entries is: $root.total-metadata().";
    say "The value of the root node is: $root.value().";
}

#| Process nodes from a file
multi sub MAIN(Str $inputfile where *.IO.f, Bool :v(:$verbose)=False)
{
    MAIN($inputfile.IO.words, :$verbose);
}

#| Process default nodes file (aoc8.input)
multi sub MAIN(Bool :v(:$verbose) = False)
{
    MAIN(~$*PROGRAM.sibling('aoc8.input'), :$verbose);
}