Data commit

Task/Ackermann-function/Perl/ackermann-function-1.pl

@@ -0,0 +1,13 @@
+{
+    my @memo;
+    sub A {
+        my( $m, $n ) = @_;
+        $memo[ $m ][ $n ] and return $memo[ $m ][ $n ];
+        $m or return $n + 1;
+        return $memo[ $m ][ $n ] = (
+            $n
+               ? A( $m - 1, A( $m, $n - 1 ) )
+               : A( $m - 1, 1 )
+        );
+    }
+}

Task/Ackermann-function/Perl/ackermann-function-2.pl

@@ -0,0 +1,6 @@
+sub A {
+    my ($m, $n) = @_;
+    if    ($m == 0) { $n + 1 }
+    elsif ($n == 0) { A($m - 1, 1) }
+    else            { A($m - 1, A($m, $n - 1)) }
+}

Task/Ackermann-function/Perl/ackermann-function-3.pl

@@ -0,0 +1,6 @@
+sub A {
+  my ($m, $n) = @_;
+  $m == 0 ? $n + 1 :
+  $n == 0 ? A($m - 1, 1) :
+            A($m - 1, A($m, $n - 1))
+}

Task/Ackermann-function/Perl/ackermann-function-4.pl

@@ -0,0 +1,15 @@
+use Memoize;  memoize('ack2');
+use bigint try=>"GMP";
+
+sub ack2 {
+   my ($m, $n) = @_;
+   $m == 0 ? $n + 1 :
+   $m == 1 ? $n + 2 :
+   $m == 2 ? 2*$n + 3 :
+   $m == 3 ? 8 * (2**$n - 1) + 5 :
+   $n == 0 ? ack2($m-1, 1)
+           : ack2($m-1, ack2($m, $n-1));
+}
+print "ack2(3,4) is ", ack2(3,4), "\n";
+print "ack2(4,1) is ", ack2(4,1), "\n";
+print "ack2(4,2) has ", length(ack2(4,2)), " digits\n";

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";