As always there are non recursive solutions. This one is 14 lines long if you exclude the animation code.
#!/usr/bin/perl -w
print "Number of disks? ";
chomp( my $numdisks = <STDIN> );
print "Sleep? ";
chomp( my $sleep = <STDIN> );
$numdisks ||= 8;
$sleep ||= 0.1;
my $board = [ [], [], [], [] ];
push @{$board->[1]}, $_ for reverse 1 .. $numdisks;
my %tower = map{ my $str =' 'x($numdisks-$_).'o'x$_;
$str = $str.($_?'+':'|').reverse($str);
$_, " $str " } 0..$numdisks;
hanoi( $numdisks );
sub hanoi {
my $n = shift;
my $n1 = $n+1;
my @D = (1)x$n1;
my @s = 1..$n1+1;
my $dir = 1 & $n;
for(;;) {
my $i = $s[0];
do{ show($n,0,0,1); last } if $i>$n;
my $to =($D[$i]+($i&1?$dir:1-$dir))%3+1;
show( $i, $D[$i], $to );
$D[$i] = $to;
$s[0] = 1;
$s[$i-1] = $s[$i];
$s[$i] = $i+1;
}
}
sub show {
my ( $num, $from, $to, $show_final ) = @_;
$^O =~ m/Win32/ ? system("cls") : system("clear");
for my $i( reverse 0..$numdisks ) {
print "\n", map{$tower{ $board->[$_]->[$i] || 0} }1..3;
}
return if $show_final;
push @{$board->[$to]}, pop @{$board->[$from]};
print "\n\nMove disk $num from $from to $to\n";
select undef, undef, undef, $sleep;
}
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