use strict; use warnings; my $target = "cowboycatdogcat"; my @partsList = qw(cow boy cat dog cat); my %partsLu; ++$partsLu{$_} for @partsList; search ($target, {%partsLu}, []); sub search { my ($target, $partsLu, $used) = @_; unless (length $target) { print join ("-", @$used), "\n"; return; } for my $part (keys %$partsLu) { next unless 0 == index $target, $part; my $remainder = substr $target, length $part; delete $partsLu->{$part} unless --$partsLu->{$part}; search ($remainder, {%$partsLu}, [@$used, $part]); } } #### cow-boy-cat-dog-cat