5 files changed, 127 insertions, 0 deletions
diff --git a/challenge-175/paulo-custodio/Makefile b/challenge-175/paulo-custodio/Makefile
new file mode 100644
index 0000000000..c3c762d746
--- /dev/null
+++ b/challenge-175/paulo-custodio/Makefile
@@ -0,0 +1,2 @@
+all:
+	perl ../../challenge-001/paulo-custodio/test.pl
diff --git a/challenge-175/paulo-custodio/perl/ch-1.pl b/challenge-175/paulo-custodio/perl/ch-1.pl
new file mode 100644
index 0000000000..7df64e1d95
--- /dev/null
+++ b/challenge-175/paulo-custodio/perl/ch-1.pl
@@ -0,0 +1,42 @@
+#!/usr/bin/perl
+
+# Challenge 175
+#
+# Task 1: Last Sunday
+# Submitted by: Mohammad S Anwar
+#
+# Write a script to list Last Sunday of every month in the given year.
+#
+# For example, for year 2022, we should get the following:
+#
+# 2022-01-30
+# 2022-02-27
+# 2022-03-27
+# 2022-04-24
+# 2022-05-29
+# 2022-06-26
+# 2022-07-31
+# 2022-08-28
+# 2022-09-25
+# 2022-10-30
+# 2022-11-27
+# 2022-12-25
+
+use Modern::Perl;
+use DateTime;
+
+sub last_sunday_month {
+    my($year, $month) = @_;
+    my $date = DateTime->last_day_of_month(year=>$year, month=>$month);
+    $date->add(days=>-1) while $date->day_of_week() != 7;
+    return $date;
+}
+
+sub last_sunday_year {
+    my($year) = @_;
+    return map {last_sunday_month($year, $_)} 1..12;
+}
+
+@ARGV==1 or die "usage: ch-1.pl year\n";
+my $year = shift;
+say $_->ymd for last_sunday_year($year);
diff --git a/challenge-175/paulo-custodio/perl/ch-2.pl b/challenge-175/paulo-custodio/perl/ch-2.pl
new file mode 100644
index 0000000000..bb1e537129
--- /dev/null
+++ b/challenge-175/paulo-custodio/perl/ch-2.pl
@@ -0,0 +1,61 @@
+#!/usr/bin/perl
+
+# Challenge 175
+#
+# Task 2: Perfect Totient Numbers
+# Submitted by: Mohammad S Anwar
+#
+# Write a script to generate first 20 Perfect Totient Numbers. Please checkout
+# wikipedia page for more informations.
+#
+# Output
+#
+# 3, 9, 15, 27, 39, 81, 111, 183, 243, 255, 327, 363, 471, 729,
+# 2187, 2199, 3063, 4359, 4375, 5571
+
+use Modern::Perl;
+
+sub gcd {
+    my($a, $b) = @_;
+    if ($a == 0) {
+        return $b;
+    }
+    else {
+        return gcd($b % $a, $a);
+    }
+}
+
+sub totient {
+    my($n) = @_;
+    my $count = 0;
+    for my $i (1..$n) {
+        $count++ if gcd($n, $i) == 1;
+    }
+    return $count;
+}
+
+sub is_perfect_totient {
+    my($n) = @_;
+    my $sum = 0;
+    my $tot = $n;
+    while ($tot != 1) {
+        $tot = totient($tot);
+        $sum += $tot;
+    }
+    return $sum == $n;
+}
+
+sub perfect_totients {
+    my($N) = @_;
+    my @result;
+    my $n = 1;
+    while (@result < $N) {
+        push @result, $n if is_perfect_totient($n);
+        $n++;
+    }
+    return @result;
+}
+
+@ARGV==1 or die "usage: ch-2.pl N\n";
+my $N = shift;
+say join ", ", perfect_totients($N);
diff --git a/challenge-175/paulo-custodio/t/test-1.yaml b/challenge-175/paulo-custodio/t/test-1.yaml
new file mode 100644
index 0000000000..8b5cb3ecb5
--- /dev/null
+++ b/challenge-175/paulo-custodio/t/test-1.yaml
@@ -0,0 +1,17 @@
+- setup:
+  cleanup:
+  args:     2022
+  input:
+  output:   |
+            |2022-01-30
+            |2022-02-27
+            |2022-03-27
+            |2022-04-24
+            |2022-05-29
+            |2022-06-26
+            |2022-07-31
+            |2022-08-28
+            |2022-09-25
+            |2022-10-30
+            |2022-11-27
+            |2022-12-25
diff --git a/challenge-175/paulo-custodio/t/test-2.yaml b/challenge-175/paulo-custodio/t/test-2.yaml
new file mode 100644
index 0000000000..1229c6897b
--- /dev/null
+++ b/challenge-175/paulo-custodio/t/test-2.yaml
@@ -0,0 +1,5 @@
+- setup:
+  cleanup:
+  args:     20
+  input:
+  output:   3, 9, 15, 27, 39, 81, 111, 183, 243, 255, 327, 363, 471, 729, 2187, 2199, 3063, 4359, 4375, 5571