package Organism;

use strict;
# use warnings;

sub _pack {
   my ( $x, $y ) = @_;
   $x < 0 ? -(abs($x) << 16 | $y) : $x << 16 | $y;
}

sub _unpack {
   my ( $n ) = @_;
   return $n < 0
      ? ( -( abs($n) >> 16 ), abs($n) & 0xFFFF )
      : (        $n  >> 16  ,     $n  & 0xFFFF );
}

sub count {
   return scalar keys %{ shift->{Cells} };
}

# Input a list of [ x, y ] coords
sub insert_cells {
   my $cells = shift->{Cells};
   for my $r (@_) { $cells->{ _pack @{$r} } = undef }
}

# Return sorted list of cells in the Organism.
# Used for verification and testing the state of the organism.
sub get_live_cells {
   sort { $a->[0] <=> $b->[0] || $a->[1] <=> $b->[1] }
      map { [ _unpack $_ ] }
      keys %{ shift->{Cells} };
}

sub tick {
   my $self  = shift;
   my $cells = $self->{Cells};
   my ( $k1, $k2, $k3, $k4, $k5, $k6, $k7, $k8,
        $x0, $x1, $x2, $y0, $y1, $y2, %new_cells, %dead_cells );

   for my $c (keys %{ $cells }) {
      # Get the (up to 8) dead cells surrounding the cell
      ( $x0, $y0 ) = $c < 0
         ? ( -( abs($c) >> 16 ), abs($c) & 0xFFFF )
         : (        $c  >> 16  ,     $c  & 0xFFFF );

      ( $x1, $x2, $y1, $y2 ) = ( $x0 - 1, $x0 + 1, $y0 - 1, $y0 + 1 );

      $dead_cells{$_}++ for my @zcells = (
         ($k1 = $x1 < 0 ? -(abs($x1) << 16 | $y1) : $x1 << 16 | $y1) x
+ !(exists $cells->{$k1}),
         ($k2 = $x1 < 0 ? -(abs($x1) << 16 | $y0) : $x1 << 16 | $y0) x
+ !(exists $cells->{$k2}),
         ($k3 = $x1 < 0 ? -(abs($x1) << 16 | $y2) : $x1 << 16 | $y2) x
+ !(exists $cells->{$k3}),
         ($k4 = $x0 < 0 ? -(abs($x0) << 16 | $y1) : $x0 << 16 | $y1) x
+ !(exists $cells->{$k4}),
         ($k5 = $x0 < 0 ? -(abs($x0) << 16 | $y2) : $x0 << 16 | $y2) x
+ !(exists $cells->{$k5}),
         ($k6 = $x2 < 0 ? -(abs($x2) << 16 | $y1) : $x2 << 16 | $y1) x
+ !(exists $cells->{$k6}),
         ($k7 = $x2 < 0 ? -(abs($x2) << 16 | $y0) : $x2 << 16 | $y0) x
+ !(exists $cells->{$k7}),
         ($k8 = $x2 < 0 ? -(abs($x2) << 16 | $y2) : $x2 << 16 | $y2) x
+ !(exists $cells->{$k8}) );

      # Check the live cell
      # Note: next line equivalent to nlive == 2 || nlive == 3
      @zcells == 5 || @zcells == 6 and $new_cells{$c} = undef;
   }
   $dead_cells{$_} == 3 and $new_cells{$_} = undef for keys %dead_cell
+s;
   $self->{Cells} = \%new_cells;
}

sub new {
   my $class = shift;
   my %init_self = ( Cells => {} );
   bless \%init_self, $class;
}

1;
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