http://qs321.pair.com?node_id=1148972


in reply to Tree Structure Challenge

Here the naive approach, no time to do the performant part now

I didn't implement a class or objects, just array for leaves and a hash %parent for the parent relation.

use strict; use warnings; use Data::Dump qw/pp/; my $tree = { Mammal => { Bovine => ["Cow", "Bison"], Canine => ["Dog", "Fox", "Wolf"], Equine => ["Horse", "Zebra", "Pony"], }, Reptile => { Bird => ["Pigeon", "Canary", "Owl"], Lizard => ["Salamander", "Chameleon"], Snake => ["Python", "Cobra"], }, }; my %parent; init_parent($tree,""); #pp \%parent; naive([qw/Cobra/],[qw/Fox/]); naive([qw/Dog Fox Wolf/],[qw/Fox/]); sub naive { my ($a,$b) =@_; my $h_a = pedigree(@$a); my $h_b = pedigree(@$b); my %add= %$h_b; delete @add{keys %$h_a}; my %delete= %$h_a; delete @delete{keys %$h_b}; pp [ [keys %add], [keys %delete]]; } sub pedigree { my @children = @_; my %nodes; @nodes{@children}=(); while (my @parents = @parent{@children} ) { #pp \@parents; @nodes{@parents}=@children; last if exists $nodes{""}; @children=@parents; } \%nodes; } sub init_parent { my ($tree,$parent) = @_; if (ref $tree eq "HASH") { while (my($key,$subtree) =each %$tree) { $parent{$key}=$parent; init_parent($subtree, $key); } } elsif (ref $tree eq "ARRAY") { for my $leave (@$tree) { $parent{$leave} = $parent; } } else { die "Corrupt Tree $tree"; } }

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!