Pattern decoding

Question

I need a little help in the following. I have this kind of datafile:

0 0    # <--- Group 1 -- 1 house (0) and 1 room (0)

0 0    # <--- Group 2 -- 2 ho         


        

Answer 1

Perl solution. It converts the input into this format:

1|0
2|1 2
3|2
4|0 0 0 0
5|0
6|0

The first column is group number, in second column there are number of rooms (minus one) of all its houses, sorted. To search for group with two different houses with 2 and 3 rooms, you can just grep '|1 2$', to search for groups with just one house with one room, grep '|0$'

#!/usr/bin/perl
#-*- cperl -*-

#use Data::Dumper;

use warnings;
use strict;

sub report {
    print join ' ', sort {$a <=> $b} @_;
    print "\n";
}

my $group = 1;
my @last = (0);
print '1|';
my @houses = ();
while (<>) {
    if (/^$/) { # group end
        report(@houses, $last[1]);
        undef @houses;
        print ++$group, '|';
        @last = (0);
    } else {
        my @tuple = split;
        if ($tuple[0] != $last[0]) { # new house
            push @houses, $last[1];
        }
        @last = @tuple;
    }
}

report(@houses, $last[1]);

It is based on the fact that for each house, only the last line is important.