22.pl

   1 #!/usr/bin/perl -w
   2
   3 use strict;
   4
   5 my @seats = map { chomp; [ split // ] } (<>);
   6
   7 my $cols = @{ $seats[0] };
   8 my $rows = @seats;
   9
  10 print "$cols x $rows\n";
  11
  12 my @neighs;
  13 for my $row (0 .. $rows-1) {
  14         my @neigh_row;
  15         for my $col (0 .. $cols-1) {
  16                 my @neigh_seats;
  17                 for my $add ([-1, -1], [-1, 0], [-1, 1],
  18                         [0, -1], [0, 1],
  19                         [1, -1], [1, 0], [1, 1]) {
  20                         my ($row1, $col1) = ($row, $col);
  21                         while (1) {
  22                                 $row1 += $add->[0];
  23                                 $col1 += $add->[1];
  24                                 last if $row1 >= $rows || $row1 < 0
  25                                         || $col1 >= $cols || $col1 < 0;
  26                                 if ($seats[$row1]->[$col1] ne '.') {
  27                                         push @neigh_seats, [$row1, $col1];
  28                                         last;
  29                                 }
  30                         }
  31                 }
  32                 push @neigh_row, \@neigh_seats;
  33         }
  34         push @neighs, \@neigh_row;
  35 }
  36
  37 while (1) {
  38         my $was_change = 0;
  39         my $occup = 0;
  40         my @newseats;
  41         for my $row (0 .. $rows-1) {
  42                 my @newrow;
  43                 for my $col (0 .. $cols-1) {
  44                         my $neigh = '';
  45                         for my $nl (@{ $neighs[$row]->[$col] }) {
  46                                 $neigh .= $seats[$nl->[0]]->[$nl->[1]];
  47                         }
  48                         my $neigh_empty =()= $neigh =~ /L/g;
  49                         my $neigh_occup =()= $neigh =~ /#/g;
  50
  51                         if ($seats[$row]->[$col] eq 'L' && !$neigh_occup) {
  52                                 push @newrow, '#';
  53                                 $was_change = 1;
  54                                 $occup++;
  55                         } elsif ($seats[$row]->[$col] eq '#' && $neigh_occup >= 5) {
  56                                 push @newrow, 'L';
  57                                 $was_change = 1;
  58                         } else {
  59                                 push @newrow, $seats[$row]->[$col];
  60                                 $occup++ if $seats[$row]->[$col] eq '#';
  61                         }
  62                 }
  63                 push @newseats, \@newrow;
  64         }
  65         @seats = @newseats;
  66         # for my $row (@seats) {
  67         #       print @$row, "\n";
  68         # }
  69         print "$occup occupied seats\n";
  70         # print "\n";
  71         last if !$was_change;
  72 }
  73
  74