50 lines
952 B
Perl
50 lines
952 B
Perl
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use lib qw/ . /;
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package Part1;
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use 5.36.0;
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use List::AllUtils qw/ uniq /;
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use Math::Vector::Real;
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use Algorithm::Combinatorics qw(permutations variations);
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use Grid;
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no warnings qw/ uninitialized /;
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sub read_input ($file) {
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Grid->new( grid =>[
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map { [ split '' ] }
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$file->lines({chomp=>1}) ]);
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}
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sub find_antinodes($grid,@group) {
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my %antinodes;
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my $iter = variations(\@group,2);
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while( my $p = $iter->next ) {
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my( $x, $y) = @$p;
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my $new = 2*$y-$x;
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$antinodes{$new}++ if $grid->is_inside(@$new);
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}
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return keys %antinodes;
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}
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sub solve ($grid) {
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my %groups;
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$grid->foreach( sub($l,$r,$content) {
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return if $content eq '.';
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my $g = ( $groups{$content} //= [] );
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push @$g, V($l,$r);
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});
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my %antinodes;
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for my $group ( values %groups ) {
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$antinodes{$_}++ for find_antinodes($grid,@$group);
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}
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return scalar keys %antinodes;
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}
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1;
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