3 files changed, 63 insertions, 0 deletions
diff --git a/challenge-160/dave-jacoby/blog.txt b/challenge-160/dave-jacoby/blog.txt
new file mode 100644
index 0000000000..0d02dfb42d
--- /dev/null
+++ b/challenge-160/dave-jacoby/blog.txt
@@ -0,0 +1 @@
+https://jacoby.github.io/2022/04/12/does-that-make-friendship-equal-four-weekly-challenge-160.html
diff --git a/challenge-160/dave-jacoby/perl/ch-1.pl b/challenge-160/dave-jacoby/perl/ch-1.pl
new file mode 100644
index 0000000000..dc08362edb
--- /dev/null
+++ b/challenge-160/dave-jacoby/perl/ch-1.pl
@@ -0,0 +1,27 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature qw{ say postderef signatures state };
+no warnings qw{ experimental };
+
+use Carp;
+use Getopt::Long;
+use Lingua::EN::Numbers qw(num2en);
+
+my $n = 6;
+GetOptions( 'number=i' => \$n, );
+croak 'Out of range' if $n < 1;
+
+say magic($n);
+
+sub magic ( $i ) {
+    return 'four is magic.' if $i == 4;
+    my $w   = num2en($i);
+    my $c   = () = $w =~ /(\w)/gmix;
+    my $d   = num2en($c);
+    my $out = qq{$w is $d, };
+    $out .= magic($c);
+    return ucfirst lc $out;
+}
+
diff --git a/challenge-160/dave-jacoby/perl/ch-2.pl b/challenge-160/dave-jacoby/perl/ch-2.pl
new file mode 100644
index 0000000000..4543ed01dc
--- /dev/null
+++ b/challenge-160/dave-jacoby/perl/ch-2.pl
@@ -0,0 +1,35 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature qw{ say postderef signatures state };
+no warnings qw{ experimental };
+
+use List::Util qw{ sum0 };
+
+my @examples;
+push @examples, [ 1, 3, 5, 7, 9 ];
+push @examples, [ 1, 2, 3, 4, 5 ];
+push @examples, [ 2, 4, 2 ];
+
+for my $e (@examples) {
+    my $i  = equilibrium_index( $e->@* );
+    my $ee = join ', ', $e->@*;
+
+    say <<"END";
+        Input:  \@n = $ee
+        Output: $i
+END
+}
+
+sub equilibrium_index ( @array ) {
+
+    for my $i ( 1 .. $#array - 1 ) {
+        my @s1 = @array[ 0 .. $i - 1 ];
+        my @s2 = @array[ $i + 1 .. $#array ];
+        my $sum1 = sum0 @s1;
+        my $sum2 = sum0 @s2;
+        return $i if $sum1 == $sum2;
+    }
+    return -1;
+}