better ways than brute force

1 files changed, 29 insertions, 0 deletions

diff --git a/challenge-043/markus-holzer/perl6/lib/Math/SelfDescriptiveNumbers.pm6 b/challenge-043/markus-holzer/perl6/lib/Math/SelfDescriptiveNumbers.pm6
new file mode 100644
index 0000000000..8409826549
--- /dev/null
+++ b/challenge-043/markus-holzer/perl6/lib/Math/SelfDescriptiveNumbers.pm6
@@ -0,0 +1,29 @@
+unit module Math::SelfDescriptiveNumbers;
+
+multi sub is-self-descriptive( Int $number, Int $base ) is export {
+    is-self-descriptive( :$number, :$base );
+}
+
+multi sub is-self-descriptive( Int :$number, Int :$base ) is export {
+    $number ∈ self-descriptive-numbers-of( $base );
+}
+
+multi sub is-self-descriptive( Str $number, Int $base ) is export {
+    is-self-descriptive( :$number, :$base );
+}
+
+multi sub is-self-descriptive( Str :$number, Int :$base ) is export {
+    parse-base( $number, $base ) ∈ self-descriptive-numbers-of( $base );
+}
+
+sub self-descriptive-numbers is export {
+    ( 1 .. 36 ).map({ ( $_, self-descriptive-numbers-of( $_ ) ) });
+}
+
+multi sub self-descriptive-numbers-of( Int $base where $_ ~~ 1|2|3|6 ) is export { () }
+multi sub self-descriptive-numbers-of( Int $base where $_ == 4 ) is export { (100, 136) }
+multi sub self-descriptive-numbers-of( Int $base where $_ == 5 ) is export { (1425) }
+multi sub self-descriptive-numbers-of( Int $base ) is export { 
+    ( parse-base( ($base - 4).base( $base ) ~  "21" ~ ( '0' x ($base - 7) ) ~ '1000', $base ) )
+}
+