From 01abcc4707c7ec90cca53911b106dca663a44bde Mon Sep 17 00:00:00 2001
From: Alexander Pankoff <ccntrq@screenri.de>
Date: Mon, 13 Dec 2021 19:34:06 +0100
Subject: Add solution for challenge 143 part 1

---
 challenge-143/alexander-pankoff/perl/ch-1.pl | 7 +++++++
 1 file changed, 7 insertions(+)
 create mode 100755 challenge-143/alexander-pankoff/perl/ch-1.pl

diff --git a/challenge-143/alexander-pankoff/perl/ch-1.pl b/challenge-143/alexander-pankoff/perl/ch-1.pl
new file mode 100755
index 0000000000..5e18a29391
--- /dev/null
+++ b/challenge-143/alexander-pankoff/perl/ch-1.pl
@@ -0,0 +1,7 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+my $expr = $ARGV[0];
+die "invalid expr\n" unless $expr && $expr =~ m/^[\s\d\.\+\-\*\*\(\)]*$/;
+print eval($expr) . "\n";
-- 
cgit 


From 50e1d3c36fa027ad2aa3ef5f1b3d07c878778d0d Mon Sep 17 00:00:00 2001
From: Alexander Pankoff <ccntrq@screenri.de>
Date: Mon, 13 Dec 2021 19:34:16 +0100
Subject: Add solution for challenge 143 part 2

---
 challenge-143/alexander-pankoff/perl/ch-2.pl | 61 ++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100755 challenge-143/alexander-pankoff/perl/ch-2.pl

diff --git a/challenge-143/alexander-pankoff/perl/ch-2.pl b/challenge-143/alexander-pankoff/perl/ch-2.pl
new file mode 100755
index 0000000000..8eba88cc93
--- /dev/null
+++ b/challenge-143/alexander-pankoff/perl/ch-2.pl
@@ -0,0 +1,61 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+use feature qw'say signatures';
+no warnings qw'experimental::signatures';
+
+use List::Util qw'first';
+
+use constant DEBUG => $ENV{DEBUG} // 0;
+
+run() unless caller();
+
+sub run() {
+    my $stealthy = stealthy( $ARGV[0] );
+    say $stealthy ? 1 : 0;
+    explain($stealthy) if DEBUG;
+}
+
+sub stealthy($n) {
+    my @divisors = find_divisors_pairs($n);
+    my @pairs    = pairs(@divisors);
+
+    my $stealthy = first {
+        my ( $a, $b, $c, $d ) = flatten($_);
+        $a * $b == $c * $d && $a + $b == $c + $d + 1;
+    }
+    @pairs;
+
+    return $stealthy;
+}
+
+sub explain($stealthy) {
+    say "Not stealthy" && return if !$stealthy;
+    my ( $a, $b, $c, $d ) = flatten($stealthy);
+    say
+"Since $a (a) * $b (b) = $c (c) * $d (d) and $a (a) + $b (b) = $c (c) + $d (d) + 1";
+}
+
+sub pairs(@xs ) {
+    my @out;
+    for my $i ( 0 .. $#xs - 1 ) {
+        push @out, map { [ $xs[$i], $xs[$_] ] } ( $i + 1 .. $#xs );
+    }
+    return @out;
+}
+
+sub flatten($xs) {
+    map { @$_ } @$xs;
+}
+
+sub find_divisors_pairs($x) {
+    my @out;
+    my $max = sqrt($x);
+    for my $i ( 1 .. $max ) {
+        if ( $x % $i == 0 ) {
+            push @out, [ $i, $x / $i ];
+        }
+    }
+
+    return @out;
+}
-- 
cgit 


From ff1256a60687a9903b39c0887e3c64115748b90d Mon Sep 17 00:00:00 2001
From: Alexander Pankoff <ccntrq@screenri.de>
Date: Tue, 14 Dec 2021 10:48:48 +0100
Subject: Fix formatting

---
 challenge-143/alexander-pankoff/perl/ch-2.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/challenge-143/alexander-pankoff/perl/ch-2.pl b/challenge-143/alexander-pankoff/perl/ch-2.pl
index 8eba88cc93..a952866cde 100755
--- a/challenge-143/alexander-pankoff/perl/ch-2.pl
+++ b/challenge-143/alexander-pankoff/perl/ch-2.pl
@@ -36,7 +36,7 @@ sub explain($stealthy) {
 "Since $a (a) * $b (b) = $c (c) * $d (d) and $a (a) + $b (b) = $c (c) + $d (d) + 1";
 }
 
-sub pairs(@xs ) {
+sub pairs(@xs) {
     my @out;
     for my $i ( 0 .. $#xs - 1 ) {
         push @out, map { [ $xs[$i], $xs[$_] ] } ( $i + 1 .. $#xs );
-- 
cgit 


From 7172edadbb0b471cdc3570098fe3f9e3160699e6 Mon Sep 17 00:00:00 2001
From: Alexander Pankoff <ccntrq@screenri.de>
Date: Tue, 14 Dec 2021 10:49:21 +0100
Subject: Remove duplicate char from match group

---
 challenge-143/alexander-pankoff/perl/ch-1.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/challenge-143/alexander-pankoff/perl/ch-1.pl b/challenge-143/alexander-pankoff/perl/ch-1.pl
index 5e18a29391..fcb9c8edbc 100755
--- a/challenge-143/alexander-pankoff/perl/ch-1.pl
+++ b/challenge-143/alexander-pankoff/perl/ch-1.pl
@@ -3,5 +3,5 @@ use strict;
 use warnings;
 
 my $expr = $ARGV[0];
-die "invalid expr\n" unless $expr && $expr =~ m/^[\s\d\.\+\-\*\*\(\)]*$/;
+die "invalid expr\n" unless $expr && $expr =~ m/^[\s\d\.\+\-\*\(\)]*$/;
 print eval($expr) . "\n";
-- 
cgit