From b915d238533b3bce7af66533d1a8be82c11a1536 Mon Sep 17 00:00:00 2001
From: Simon Green <mail@simon.green>
Date: Tue, 27 Jul 2021 22:24:07 +1000
Subject: sgreen solution to challenge 123

---
 challenge-123/sgreen/README.md    |  4 +--
 challenge-123/sgreen/blog.txt     |  1 +
 challenge-123/sgreen/perl/ch-1.pl | 36 +++++++++++++++++++++++++
 challenge-123/sgreen/perl/ch-2.pl | 55 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 94 insertions(+), 2 deletions(-)
 create mode 100644 challenge-123/sgreen/blog.txt
 create mode 100755 challenge-123/sgreen/perl/ch-1.pl
 create mode 100755 challenge-123/sgreen/perl/ch-2.pl

diff --git a/challenge-123/sgreen/README.md b/challenge-123/sgreen/README.md
index 8bdfd69d11..1b1ced64d1 100644
--- a/challenge-123/sgreen/README.md
+++ b/challenge-123/sgreen/README.md
@@ -1,3 +1,3 @@
-# The Weekly Challenge 122
+# The Weekly Challenge 123
 
-Solution by Simon Green. [Blog](https://dev.to/simongreennet/weekly-challenge-122-4np8)
+Solution by Simon Green. [Blog](https://dev.to/simongreennet/weekly-challenge-123-2flk)
diff --git a/challenge-123/sgreen/blog.txt b/challenge-123/sgreen/blog.txt
new file mode 100644
index 0000000000..d7e6df3d07
--- /dev/null
+++ b/challenge-123/sgreen/blog.txt
@@ -0,0 +1 @@
+https://dev.to/simongreennet/weekly-challenge-123-2flk
diff --git a/challenge-123/sgreen/perl/ch-1.pl b/challenge-123/sgreen/perl/ch-1.pl
new file mode 100755
index 0000000000..9043d758d3
--- /dev/null
+++ b/challenge-123/sgreen/perl/ch-1.pl
@@ -0,0 +1,36 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+
+sub _is_ugly {
+    my $x = shift;
+
+    # Keep dividing by 2, 3 and 5 as long as it leaves no remainder
+    foreach my $d ( 2, 3, 5 ) {
+        while ( $x % $d == 0 ) {
+            $x /= $d;
+        }
+    }
+
+    # If the result is 1, it's an ugly number
+    return $x == 1 ? 1 : 0;
+}
+
+sub main {
+    my $n = shift;
+
+    # Sanity check
+    die "You must provide a postive integer\n" unless defined $n;
+    die "The value '$n' does not appear to be a positive integer\n" unless $n =~ /^[1-9][0-9]*$/;
+
+    my $number = 0;
+    while ($n) {
+        --$n if _is_ugly( ++$number );
+    }
+
+    say $number;
+}
+
+main(@ARGV);
diff --git a/challenge-123/sgreen/perl/ch-2.pl b/challenge-123/sgreen/perl/ch-2.pl
new file mode 100755
index 0000000000..6fcd85b8fc
--- /dev/null
+++ b/challenge-123/sgreen/perl/ch-2.pl
@@ -0,0 +1,55 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+
+# These constants makes it easier to explain
+use constant X1 => 0;
+use constant Y1 => 1;
+use constant X2 => 2;
+use constant Y2 => 3;
+use constant X3 => 4;
+use constant Y3 => 5;
+use constant X4 => 6;
+use constant Y4 => 7;
+
+sub _distance_between {
+    # Work out the distance between two points
+    my ( $x1, $y1, $x2, $y2 ) = @_;
+    my $delta_x = abs( $x1 - $x2 );
+    my $delta_y = abs( $y1 - $y2 );
+    return sqrt( $delta_x**2 + $delta_y**2 );
+}
+
+sub _is_square {
+    my @values = @_;
+
+    # Get the distance between the first two points
+    my $delta = _distance_between( @values[ X1, Y1, X2, Y2 ] );
+
+    # Make sure each side is of equal length
+    return 0 if _distance_between( @values[ X2, Y2, X3, Y3 ] ) != $delta;
+    return 0 if _distance_between( @values[ X3, Y3, X4, Y4 ] ) != $delta;
+    return 0 if _distance_between( @values[ X4, Y4, X1, Y1 ] ) != $delta;
+
+    # Make sure the two cross angles are also of the same length
+    return 0 if _distance_between( @values[ X1, Y1, X3, Y3 ] ) != _distance_between( @values[ X2, Y2, X4, Y4 ] );
+
+    # It's a square
+    return 1;
+}
+
+sub main {
+    my @values = @_;
+
+    # Sanity check
+    die "You must provide eight numbers\n" unless scalar(@values) == 8;
+    foreach my $x (@values) {
+        die "The value '$x does not appear to be a number\n" unless $x =~ /^-?[0-9]+(?:\.[1-9]+)?$/;
+    }
+
+    say _is_square(@values);
+}
+
+main(@ARGV);
-- 
cgit