From e72a0d33e191a62a83d69c6d4252fa733192ca77 Mon Sep 17 00:00:00 2001
From: Jörg Sommrey <28217714+jo-37@users.noreply.github.com>
Date: Thu, 16 Mar 2023 18:12:40 +0100
Subject: Challenge 019 task 1

---
 challenge-019/jo-37/perl/ch-1.pl | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100755 challenge-019/jo-37/perl/ch-1.pl

diff --git a/challenge-019/jo-37/perl/ch-1.pl b/challenge-019/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..b64aa0549b
--- /dev/null
+++ b/challenge-019/jo-37/perl/ch-1.pl
@@ -0,0 +1,27 @@
+#!/usr/bin/perl -s
+
+use v5.16;
+use warnings;
+use Date::Manip::Recur;
+
+main: {
+    # A month with five Fridays and five Sundays has five Saturdays,
+    # too.
+
+    # Find all months having five Fridays.
+    my @fridays = map $_->printf('%Y/%m'),
+        Date::Manip::Recur->new('5th Friday of every month',
+        undef, 1900, 2020)->dates;
+    # Find all months having five Sundays.
+    my @sundays = map $_->printf('%Y/%m'),
+        Date::Manip::Recur->new('5th Sunday of every month',
+        undef, 1900, 2020)->dates;
+
+    # Build a hash having the months with five Fridays as keys and
+    # values.
+    my %fridays;
+    @fridays{@fridays} = @fridays;
+    # Find the intersection between months with five Fridays and five
+    # Sundays.
+    say for grep defined, @fridays{@sundays};
+}
-- 
cgit