46 lines
974 B
Perl
46 lines
974 B
Perl
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use 5.38.0;
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package Part1;
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use List::AllUtils qw/pairmap max sum /;
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sub find_numbers($line) {
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my @entries;
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while ( $line =~ /\d+/g ) {
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push @entries => {
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prefix => length $`,
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length => length $&,
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n => 0+$&,
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};
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}
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return @entries;
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}
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sub near_symbol($numb,$lines) {
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no warnings;
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my $surrounding = join "", map {
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substr $lines->[$_+$numb->{line}],
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max($numb->{prefix}-1,0),
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$numb->{length}+2
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} -1..1;
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return $surrounding =~ /[^.\d]/;
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}
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sub numbers_near_symbols($input) {
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my @lines = split "\n", $input;
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unshift @lines, '';
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my @numbers = pairmap { map { +{ %$_, line => $a } } @$b } map { $_ => [find_numbers($lines[$_])] } 1..$#lines;
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@numbers = grep { near_symbol($_,\@lines) } @numbers;
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return @numbers;
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}
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sub solution_1 ($input) {
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my @numbers = numbers_near_symbols($input);
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return sum map { $_->{n}} @numbers;
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}
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1;
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