hanoi

hanoi.pl

#!/usr/bin/perl
use strict;
use warnings;

sub hanoi {
    my ($from, $to, $spare, $num) = @_;

    my $hanoi = $num > 1 ? \&hanoi : sub {};

    $hanoi->($from, $spare, $to, $num - 1);
    move($from, $to);
    $hanoi->($spare, $to, $from, $num - 1);
}

sub move { unshift @{$_[1]}, shift @{$_[0]} }

my $a = [qw/1 2 3/];
my $b = [];
my $c = [];

use Data::Dump qw/dump/;
sub yeah { print dump({a => $a, b => $b, c => $c}), $/ }

yeah;

hanoi $a, $c, $b, 0+@$a;

yeah;