Perl scripts

2 files changed, 49 insertions, 0 deletions

diff --git a/challenge-159/perl/ch-1.pl b/challenge-159/perl/ch-1.pl
new file mode 100644
index 0000000000..d6500f2c5f
--- /dev/null
+++ b/challenge-159/perl/ch-1.pl
@@ -0,0 +1,45 @@
+#!/usr/bin/perl
+# The Weekly Challenge 159
+# Task 1 Farey Sequence
+
+# https://en.wikipedia.org/wiki/Farey_sequence#Next_term
+
+use v5.22.0;
+use warnings;
+use POSIX;
+
+my $N = $ARGV[0] if defined($ARGV[0]); 
+
+say farey($N) if defined($ARGV[0]);
+
+
+
+sub farey {
+    my $n = $_[0];
+    die "The parameter should be a positive integer." if $n==0;
+    my ($g, $h) = ([0,1], [1, $n]);
+    my @terms;
+    do {
+        push @terms, "".join("/", $g->@*);
+        my ($a, $b) = $g->@*;
+        my ($c, $d) = $h->@*;
+        my ($p, $q) = (
+            $c*floor (($n+$b)/$d) - $a, 
+            $d*floor(($n+$b)/$d) - $b
+        );
+        ($g, $h) = ($h, [$p, $q]);
+    } while (!($h->[0] == 1 && $h->[1] == 1));
+    push @terms, join("/", $g->@*), join("/", $h->@*);
+    return join(", ",@terms) . ".";
+}
+
+
+
+use Test::More tests => 3;
+ok(
+    "0/1, 1/5, 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 1/1."
+    eq farey(5), "Example 1");
+ok(
+    "0/1, 1/7, 1/6, 1/5, 1/4, 2/7, 1/3, 2/5, 3/7, 1/2, 4/7, 3/5,"
+    . " 2/3, 5/7, 3/4, 4/5, 5/6, 6/7, 1/1." eq farey(7), "Example 2");
+ok("0/1, 1/4, 1/3, 1/2, 2/3, 3/4, 1/1." eq farey(4), "Example 3");
diff --git a/challenge-159/perl/ch-2.pl b/challenge-159/perl/ch-2.pl
index 8efb6f5c41..0d58c1eeb4 100644
--- a/challenge-159/perl/ch-2.pl
+++ b/challenge-159/perl/ch-2.pl
@@ -25,6 +25,8 @@ sub irn {
     );
 }
 
+
+
 sub mo {
     my $n = $_[0];
     return 1 if $n == 1;
@@ -38,6 +40,8 @@ sub mo {
     return floor(Re($sum)+0.5);
 }
 
+
+
 use Test::More tests => 18;
 ok mo(2) == -1, "test for 2";
 ok mo(5) == -1, "Example 1";