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Re: to find inter connected items

by choroba (Canon)
on Nov 04, 2012 at 08:26 UTC ( #1002173=note: print w/ replies, xml ) Need Help??


in reply to to find inter connected items

Using a hash is a good solution. I used the following algorithm: If both the numbers to be made related already belong to different classes, the classes are "merged", i.e. all numbers belonging to the class with a greater index are re-classified to the other class.

#!/usr/bin/perl use warnings; use strict; use Data::Dumper; my @a = (1, 1, 2, 3, 4, 4, 8, 8); my @b = (3, 4, 3, 5, 6, 7, 9, 10); print Dumper related(\@a, \@b); sub related { my @a = @{ +shift }; my @b = @{ +shift }; die "Different length.\n" if @a != @b; my %r; PAIR: for my $i (0 .. $#a) { my @classes; for my $e ($a[$i], $b[$i]) { push @classes, $r{$e} if exists $r{$e}; } # Both numbers already classified. Merge their classes if diff +erent. if (@classes == 2) { next PAIR if $classes[0] == $classes[1]; my ($min, $max) = sort { $a <=> $b } @r{$a[$i], $b[$i]}; $r{$_} = $min for grep $r{$_} == $max, keys %r; # Just one number already classified. Classify the second one +to the same class. } elsif (@classes == 1) { if (exists $r{$a[$i]}) { $r{$b[$i]} = $r{$a[$i]}; } else { $r{$a[$i]} = $r{$b[$i]}; } # Both numbers are seen for the first time. } else { # @classes == 0 my $min = $a[$i] < $b[$i] ? $a[$i] : $b[$i]; @r{$a[$i], $b[$i]} = ($min) x 2; } } return \%r; }
لսႽ ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ


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