Merge pull request #5905 from adamcrussell/challenge-159

Challenge 159

3 files changed, 67 insertions, 0 deletions

diff --git a/challenge-159/adam-russell/blog.txt b/challenge-159/adam-russell/blog.txt
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index 0000000000..bec9274e05
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+++ b/challenge-159/adam-russell/blog.txt
@@ -0,0 +1 @@
+http://www.rabbitfarm.com/cgi-bin/blosxom/perl/2022/04/10
diff --git a/challenge-159/adam-russell/perl/ch-1.pl b/challenge-159/adam-russell/perl/ch-1.pl
new file mode 100644
index 0000000000..8d36c68b9b
--- /dev/null
+++ b/challenge-159/adam-russell/perl/ch-1.pl
@@ -0,0 +1,25 @@
+use strict;
+use warnings;
+##
+# You are given a positive number, $n. Write a script 
+# to compute the Farey Sequence of the order $n.
+##
+use POSIX;
+
+sub farey{
+    my($order) = @_;
+    my @farey;
+    my($s, $t, $u, $v, $x, $y) = (0, 1, 1, $order, 0, 0);
+    push @farey, "$s/$t", "$u/$v";
+    while($y != 1 && $order > 1){
+        $x = POSIX::floor(($t + $order) / $v) * $u - $s;
+        $y = POSIX::floor(($t + $order) / $v) * $v - $t;
+        push @farey, "$x/$y";
+        ($s, $t, $u, $v) = ($u, $v, $x, $y);
+    }
+    return @farey;
+}
+
+MAIN:{
+    print join(", ", farey(7)) . "\n";
+}
\ No newline at end of file
diff --git a/challenge-159/adam-russell/perl/ch-2.pl b/challenge-159/adam-russell/perl/ch-2.pl
new file mode 100644
index 0000000000..725bf897af
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+++ b/challenge-159/adam-russell/perl/ch-2.pl
@@ -0,0 +1,41 @@
+use strict;
+use warnings;
+##
+# You are given a positive number $n. Write a script 
+# to generate the Moebius Number for the given number. 
+##
+use POSIX;
+use Math::Complex;
+
+sub farey{
+    my($order) = @_;
+    my @farey;
+    my($s, $t, $u, $v, $x, $y) = (0, 1, 1, $order, 0, 0);
+    push @farey, "$s/$t", "$u/$v";
+    while($y != 1 && $order > 1){
+        $x = POSIX::floor(($t + $order) / $v) * $u - $s;
+        $y = POSIX::floor(($t + $order) / $v) * $v - $t;
+        push @farey, "$x/$y";
+        ($s, $t, $u, $v) = ($u, $v, $x, $y);
+    }
+    return @farey;
+}
+
+sub mertens{
+    my($n) = @_;
+    my @farey = farey($n);
+    my $mertens = 0;
+    map {$mertens += exp(2 * M_PI * i * eval($_))} @farey;
+    $mertens += -1;
+    return Re($mertens);
+}
+
+sub moebius{
+    my($n) = @_;
+    return 1 if $n == 1;
+    return sprintf("%.f", (mertens($n) - mertens($n - 1)));
+}
+
+MAIN:{
+    map {print moebius($_) . "\n"} (5, 10, 20);
+}
\ No newline at end of file