From 4454a107cc1abfc7bb45c239515cc4092ca7fbe3 Mon Sep 17 00:00:00 2001
From: "E. Choroba" <choroba@matfyz.cz>
Date: Mon, 11 Apr 2022 17:19:08 +0200
Subject: Solve 160: Four Is Magic & Equilibrium Index by E. Choroba

---
 challenge-160/e-choroba/perl/ch-1.pl | 27 +++++++++++++++++++++++++++
 challenge-160/e-choroba/perl/ch-2.pl | 31 +++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)
 create mode 100755 challenge-160/e-choroba/perl/ch-1.pl
 create mode 100755 challenge-160/e-choroba/perl/ch-2.pl

diff --git a/challenge-160/e-choroba/perl/ch-1.pl b/challenge-160/e-choroba/perl/ch-1.pl
new file mode 100755
index 0000000000..5aa336efb2
--- /dev/null
+++ b/challenge-160/e-choroba/perl/ch-1.pl
@@ -0,0 +1,27 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use experimental 'signatures';
+
+my @cardinals = qw( one two three four five six seven eight nine );
+
+sub four_is_magic ($n) {
+    ucfirst _four_is_magic($n) . '.'
+}
+
+sub _four_is_magic ($n) {
+    return 'four is magic' if 4 == $n;
+
+    my $word = $cardinals[ $n - 1 ];
+    my $length = length $word;
+    return "$word is $cardinals[ $length - 1 ], " . _four_is_magic($length)
+}
+
+use Test::More tests => 3;
+
+is four_is_magic(5),
+    'Five is four, four is magic.', 'Example 1';
+is four_is_magic(7),
+    'Seven is five, five is four, four is magic.', 'Example 2';
+is four_is_magic(6),
+    'Six is three, three is five, five is four, four is magic.', 'Example 3';
diff --git a/challenge-160/e-choroba/perl/ch-2.pl b/challenge-160/e-choroba/perl/ch-2.pl
new file mode 100755
index 0000000000..195d7f286e
--- /dev/null
+++ b/challenge-160/e-choroba/perl/ch-2.pl
@@ -0,0 +1,31 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use experimental 'signatures';
+
+use List::Util qw{ sum };
+
+
+sub equilibrium_index ($array) {
+    my $i = 0;
+    my @sums = (0, sum(@$array) - $array->[0]);
+    my @results;
+    for my $i (1 .. $#$array - 1) {
+        $sums[0] += $array->[$i - 1];
+        $sums[1] -= $array->[$i];
+        push @results, $i if $sums[0] == $sums[1];
+    }
+
+    return @results if @results;
+
+    return -1
+}
+
+use Test::More tests => 5;
+
+is_deeply [equilibrium_index([1, 3, 5, 7, 9])], [ 3], 'Example 1';
+is_deeply [equilibrium_index([1, 2, 3, 4, 5])], [-1], 'Example 2';
+is_deeply [equilibrium_index([2, 4, 2])      ], [ 1], 'Example 3';
+
+is_deeply [equilibrium_index([1, 1, 1, -3, 7, 0])], [4], 'Negative numbers';
+is_deeply [equilibrium_index([0, 0, 0, 0])], [1, 2], 'More options';
-- 
cgit