adventofcode/2017/09/1.pl

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Perl
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2017-12-10 18:41:54 +00:00
use 5.20.0;
my $stream = <>;
chomp $stream;
$stream = clean_stream($stream);
use Text::Balanced qw/ extract_bracketed /;
use List::AllUtils qw/ sum /;
use experimental qw/signatures /;
say score( $stream );
sub score($stream,$level=1) {
$stream =~ s/.*?\{(.*)\}.*?/$1/;
my @children;
my $extracted;
while( length $stream ) {
( $extracted, $stream ) = extract_bracketed( $stream, '{}', qr/,?/ );
push @children, $extracted if length $extracted;
$stream =~ s/^,|,$//;
}
return sum $level, map { score($_,$level+1) } @children;
}
sub clean_stream {
my $s = shift;
return $s unless $s =~ s/^(.*?)<//;
my $clean = $1;
while( $s =~ s/^.*?(!!|!>|>)// ) {
last if $1 eq '>';
}
return $clean . clean_stream($s);
}