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

my %piles = (A => [reverse 1..3], B => [], C => []);

dumpPiles ();
hanoi (scalar @{$piles{A}}, keys %piles); #A

sub hanoi {
   my ($n, $start, $end, $extra, $recursion) = @_;
   print "Hanoi: Disk $n\n";
   if ($n == 1) { #B
        report ($start, $end, $recursion);
   } else {
        hanoi($n-1, $start, $extra, $end); #C
        report ($start, $end, $recursion);
        hanoi($n-1, $extra, $end, $start); #D
   }
}

sub report {
    my ($start, $end) = @_;
    my $disk = pop @{$piles{$start}};

    print "Moved disk $disk from $start to $end.\n";
    push @{$piles{$end}}, $disk;
    dumpPiles ();
}

sub dumpPiles {
    for my $pile (sort keys %piles) {
        print "$pile: @{$piles{$pile}}\n";
    }
}