Hello melmoth,

Here’s a more Perlish version of your code, using Set::Tiny for the convenience of its is_subset method:

use strict;
use warnings;
use Set::Tiny 'set';
 
my @paths =
(
    [ qw(A B F G)       ],
    [ qw(A B)           ],
    [ qw(A B X)         ],
    [ qw(A B C D E F G) ],
    [ qw(I J K L M)     ],
);

my   @sets;
push @sets, set(@$_) for @paths;
     @sets = sort { $a->size <=> $b->size } @sets;    # UPDATED
my   @filtered;

LINE: for my $i (0 .. $#sets)
{
    my $set_i = $sets[$i];

    for my $j ($i + 1 .. $#sets)
    {
        next LINE if $set_i->is_subset($sets[$j]);
    }

    push @filtered, $set_i;
}

print $_->as_string, "\n" for @filtered;

[download]

<Update> Added sort line marked # UPDATED as per BrowserUk’s post below. </Update>

Now (other things being equal), the larger the set J, the more likely it is that J is a superset of a given set I. So an obvious speedup to try is to test I against the larger sets first, by reverseing the inner loop:

for my $j (reverse($i + 1 .. $#sets))

[download]

Of course, you’ll need to Benchmark the code to determine whether this makes a significant difference for your input data.

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

In reply to Re: Fast Way to find one array in second array by Athanasius
in thread Fast Way to find one array in second array by melmoth

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