Initial data commit

Task/Ackermann-function/Perl/ackermann-function-5.pl

@@ -0,0 +1,34 @@
+use strict;
+use warnings;
+use Math::BigInt;
+
+use constant two => Math::BigInt->new(2);
+
+sub ack {
+	my $n = pop;
+	while( @_ ) {
+		my $m = pop;
+		if( $m > 3 ) {
+			push @_, (--$m) x $n;
+			push @_, reverse 3 .. --$m;
+			$n = 13;
+		} elsif( $m == 3 ) {
+			if( $n < 29 ) {
+				$n = ( 1 << ( $n + 3 ) ) - 3;
+			} else {
+				$n = two ** ( $n + 3 ) - 3;
+			}
+		} elsif( $m == 2 ) {
+			$n = 2 * $n + 3;
+		} elsif( $m >= 0 ) {
+			$n = $n + $m + 1;
+		} else {
+			die "negative m!";
+		}
+	}
+	$n;
+}
+
+print "ack(3,4) is ", ack(3,4), "\n";
+print "ack(4,1) is ", ack(4,1), "\n";
+print "ack(4,2) has ", length(ack(4,2)), " digits\n";