From e0eee17ff2e9f4f59cc6ba4e2fd5ddbde41c374e Mon Sep 17 00:00:00 2001
From: Scimon <simon.proctor@gmail.com>
Date: Tue, 5 Apr 2022 11:49:18 +0100
Subject: Challenge 2

---
 challenge-159/simon-proctor/raku/ch-1.raku |  2 +-
 challenge-159/simon-proctor/raku/ch-2.raku | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 challenge-159/simon-proctor/raku/ch-2.raku

diff --git a/challenge-159/simon-proctor/raku/ch-1.raku b/challenge-159/simon-proctor/raku/ch-1.raku
index c94a0e7bb4..1b03ac2520 100644
--- a/challenge-159/simon-proctor/raku/ch-1.raku
+++ b/challenge-159/simon-proctor/raku/ch-1.raku
@@ -1,6 +1,6 @@
 #!/usr/bin/env raku
 
-# Output the Farey Sequence of order n
+#| Output the Farey Sequence of order n
 sub MAIN ( Int \n ) {
     ((0..n) X/ (1..n)).grep( * <= 1 ).unique.sort.map( *.nude ).map( { "@_[0]/@_[1]" } ).join(", ").say
 }
diff --git a/challenge-159/simon-proctor/raku/ch-2.raku b/challenge-159/simon-proctor/raku/ch-2.raku
new file mode 100644
index 0000000000..364774c744
--- /dev/null
+++ b/challenge-159/simon-proctor/raku/ch-2.raku
@@ -0,0 +1,23 @@
+#!/usr/bin/env raku
+
+#| Given a number n print the Möbius number for it
+sub MAIN( Int() \n ) {
+    say Möbius(n);
+}
+
+multi sub prime-factors(1) { [] }
+multi sub prime-factors(Int() $x) {
+    my $p = (2..^$x).first($x %% *);
+    return $p ?? [$p, |prime-factors($x div $p)] !! [$x]
+}
+sub square-free(Int() $x) {
+    my @p = prime-factors($x);
+    @p ~~ @p.unique
+};
+sub Möbius($x) {
+    square-free($x) ??
+    (
+        prime-factors($x).elems %% 2 ?? 1 !! -1
+    )
+    !! 0;
+}
-- 
cgit