jaredor already pointed out the related post from 3 weeks ago where someone wanted to do the same thing: how to find combine common elements of an array?

However, after a little thought, I came up with a shorter solution than my original suggestion:


use strict;
use warnings;

#my @array = ([11,12], [11,13], [9,8,7], [3,4], [11,4]);
my @array = ([0], [0,1], [0,1,2], [1,2,3], [6,4,5]);

ORIG: for my $i (0..$#array) {
    for my $j ($i+1..$#array) {
        my %seen;
        my @unique = grep {! $seen{$_}++} @{$array[$i]}, @{$array[$j]}
+;
        if (@unique < @{$array[$i]} + @{$array[$j]}) {
            $array[$i] = \@unique;
            splice @array, $j, 1;
            redo ORIG;
        }
    }
}

print join(' ', @$_), "\n" for (@array);

[download]

Note: This only works if each set contains unique elements only.

In reply to Re: How can sets be recursively concatenated when intersecting with each other by wind
in thread How can sets be recursively concatenated when intersecting with each other by joni

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