From 5ff8057ec433de471554565b1ca9bea945fd66c6 Mon Sep 17 00:00:00 2001
From: "Kian-Meng, Ang" <kianmeng@users.noreply.github.com>
Date: Sun, 14 Apr 2019 22:55:55 +0800
Subject: Add challenge #3 solutions and last week blog link

---
 challenge-002/kian-meng-ang/blog.txt     |  1 +
 challenge-003/kian-meng-ang/perl5/ch1.pl | 42 ++++++++++++++++++++++++++++++++
 challenge-003/kian-meng-ang/perl5/ch2.pl | 37 ++++++++++++++++++++++++++++
 3 files changed, 80 insertions(+)
 create mode 100644 challenge-002/kian-meng-ang/blog.txt
 create mode 100644 challenge-003/kian-meng-ang/perl5/ch1.pl
 create mode 100644 challenge-003/kian-meng-ang/perl5/ch2.pl

diff --git a/challenge-002/kian-meng-ang/blog.txt b/challenge-002/kian-meng-ang/blog.txt
new file mode 100644
index 0000000000..9e54773aa0
--- /dev/null
+++ b/challenge-002/kian-meng-ang/blog.txt
@@ -0,0 +1 @@
+https://www.kianmeng.org/2019/04/perl-weekly-challenge-002-2019-week-14.html
diff --git a/challenge-003/kian-meng-ang/perl5/ch1.pl b/challenge-003/kian-meng-ang/perl5/ch1.pl
new file mode 100644
index 0000000000..765efbeabb
--- /dev/null
+++ b/challenge-003/kian-meng-ang/perl5/ch1.pl
@@ -0,0 +1,42 @@
+#!/usr/bin/env perl
+
+# See https://en.wikipedia.org/wiki/Regular_number
+# See https://en.wikipedia.org/wiki/Prime_number#Unique_factorization
+# See https://en.wikipedia.org/wiki/Smooth_number
+
+use 5.010;
+use strict;
+use warnings;
+use utf8;
+
+sub is_five_smooth_number {
+    my $number = shift;
+
+    die "Must be positive integer" if ($number < 1);
+
+    return $number if ($number <= 5);
+
+    foreach my $prime_factor (qw(2 3 5)) {
+        $number = $number / $prime_factor while ($number % $prime_factor == 0);
+    }
+    return $number == 1;
+}
+
+my $nth_number = $ARGV[0];
+die "Missing n-th smoon number" if (!$nth_number);
+
+my ($i, @five_smooth_numbers) = (1, ());
+while (scalar @five_smooth_numbers < $nth_number) {
+    push @five_smooth_numbers, $i if (is_five_smooth_number($i));
+    $i++;
+}
+
+say join("|", @five_smooth_numbers);
+
+
+1;
+# vi:et:sw=4 ts=4 ft=perl
+
+__END__
+$ perl ch1.pl 30
+1|2|3|4|5|6|8|9|10|12|15|16|18|20|24|25|27|30|32|36|40|45|48|50|54|60|64|72|75|80
diff --git a/challenge-003/kian-meng-ang/perl5/ch2.pl b/challenge-003/kian-meng-ang/perl5/ch2.pl
new file mode 100644
index 0000000000..78568cb353
--- /dev/null
+++ b/challenge-003/kian-meng-ang/perl5/ch2.pl
@@ -0,0 +1,37 @@
+#!/usr/bin/env perl
+
+# See https://en.wikipedia.org/wiki/Pascal%27s_triangle#Calculating_a_row_or_diagonal_by_itself
+# See https://www.mathsisfun.com/pascals-triangle.html
+
+use 5.010;
+use strict;
+use warnings;
+use utf8;
+
+sub generate_pascal_row {
+    my $n = shift;
+
+    my @rows = (1);
+    foreach my $k (0..$n - 1) {
+        push @rows, $rows[$k] * ($n - $k) / ($k + 1);
+    }
+    return \@rows;
+}
+
+my $n = $ARGV[0] || die "Expect number of row";
+say "$_: @{generate_pascal_row($_)}" for (0..$n);
+
+1;
+# vi:et:sw=4 ts=4 ft=perl
+
+__END__
+$ perl ch2.pl 8
+0: 1
+1: 1 1
+2: 1 2 1
+3: 1 3 3 1
+4: 1 4 6 4 1
+5: 1 5 10 10 5 1
+6: 1 6 15 20 15 6 1
+7: 1 7 21 35 35 21 7 1
+8: 1 8 28 56 70 56 28 8 1
-- 
cgit