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

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

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

sub hanoi {
   my ($n, $start, $end, $extra) = @_;
   if ($n == 1) {
        report ($start, $end);
   } else {
        hanoi($n-1, $start, $extra, $end);
        report ($start, $end);
        hanoi($n-1, $extra, $end, $start);
   }
}

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";
    }
}

##</code><code>##

A: 3 2 1
B: 
C: 
Moved disk 1 from A to C.
A: 3 2
B: 
C: 1
Moved disk 2 from A to B.
A: 3
B: 2
C: 1
Moved disk 1 from C to B.
A: 3
B: 2 1
C: 
Moved disk 3 from A to C.
A: 
B: 2 1
C: 3
Moved disk 1 from B to A.
A: 1
B: 2
C: 3
Moved disk 2 from B to C.
A: 1
B: 
C: 3 2
Moved disk 1 from A to C.
A: 
B: 
C: 3 2 1