Merge pull request #6006 from PerlBoy1967/branch-for-challenge-162

Wk 162 - Task 1 & 2

2 files changed, 126 insertions, 0 deletions

diff --git a/challenge-162/perlboy1967/perl/ch-1.pl b/challenge-162/perlboy1967/perl/ch-1.pl
new file mode 100755
index 0000000000..6d55acdfc3
--- /dev/null
+++ b/challenge-162/perlboy1967/perl/ch-1.pl
@@ -0,0 +1,25 @@
+#!/bin/perl
+
+=pod
+
+The Weekly Challenge - 162
+ - https://perlweeklychallenge.org/blog/perl-weekly-challenge-162/#TASK1
+
+Author: Niels 'PerlBoy' van Dijke
+
+Task 1: ISBN-13
+Submitted by: Mohammad S Anwar
+
+Write a script to generate the check digit of given ISBN-13 code. Please refer to 
+wikipedia for more information.
+
+=cut
+
+use v5.16;
+
+use List::Util qw(sum0);
+use List::MoreUtils qw(pairwise);
+
+my @isbnDigits = (grep/\d/,split//,shift // '978-0-306-40615-7')[0..11];
+my @factors = split//,1313131313131;
+printf "%d\n", (10 - (sum0 pairwise {$a*$b} @isbnDigits,@factors) % 10) % 10;
diff --git a/challenge-162/perlboy1967/perl/ch-2.pl b/challenge-162/perlboy1967/perl/ch-2.pl
new file mode 100755
index 0000000000..9f96f473d8
--- /dev/null
+++ b/challenge-162/perlboy1967/perl/ch-2.pl
@@ -0,0 +1,101 @@
+#!/bin/perl
+
+=pod
+
+The Weekly Challenge - 162
+ - https://perlweeklychallenge.org/blog/perl-weekly-challenge-162/#TASK2
+
+Author: Niels 'PerlBoy' van Dijke
+
+Task 2: Wheatstone-Playfair
+Submitted by: Roger Bell_West
+
+Implement encryption and decryption using the Wheatstone-Playfair cipher.
+
+=cut
+
+use v5.16;
+
+use constant WP_ENCRYPT => 1;
+use constant WP_DECRYPT => -1;
+
+use Test::More;
+
+is(encrypt('playfair example', 'hide the gold in the tree stump'), 'bmodzbxdnabekudmuixmmouvif');
+is(decrypt('perl and raku', 'siderwrdulfipaarkcrw'), 'thewexeklychallengex');
+
+done_testing();
+
+
+sub encrypt ($$) {
+  _wpCrypt($_[0],$_[1],WP_ENCRYPT);
+}
+
+
+sub decrypt ($$) {
+  _wpCrypt($_[0],$_[1],WP_DECRYPT);
+}
+
+
+sub _wpCrypt ($$$) {
+  my ($key,$text,$mode) = (lc $_[0], lc $_[1], $_[2]);
+
+  my ($hrC2L,$arL2C,@return);
+
+  # Remove spaces from key
+  $key =~ s/\s//g;
+
+  my @keyChars = split//,$key;
+  my %chars = map { $_ => 1 } ('a' .. 'z');
+  my %usedChars;
+
+  # Build encryption matrix
+  for my $row (0..4) {
+    for my $col (0..4) {
+      my $char;
+      do {
+        $char = (scalar @keyChars ? shift @keyChars : (sort keys %chars)[0]);
+        delete $chars{$char};
+        delete $chars{j} if $char eq 'i';
+        delete $chars{i} if $char eq 'j';
+      } while (exists $usedChars{$char});
+      $hrC2L->{$char} = [$row,$col];
+      $arL2C->[$row][$col] = $char;
+      $usedChars{$char} = 1;
+      $usedChars{j} = 1 if $char eq 'i';
+      $usedChars{i} = 1 if $char eq 'j';
+    }
+  }
+
+  # Remove spaces from text
+  $text =~ s/\s//g;
+
+  # On ecryption, insert 'x' before repeating characters
+  $text =~ s/(.)(?=\1)/$1x/g
+    if $mode == WP_ENCRYPT;
+
+  # Process per 2 chars of plaintext
+  while ($text =~ s#^(.)(.)?##c) {
+    my ($char1,$char2) = ($1, $2 // 'x');
+
+    my ($c1,$c2) = ($hrC2L->{$char1},$hrC2L->{$char2});
+
+    # Coords form rectangle?
+    if ($c1->[0] != $c2->[0] and $c1->[1] != $c2->[1]) {
+      push(@return,$arL2C->[$c1->[0]][$c2->[1]]);
+      push(@return,$arL2C->[$c2->[0]][$c1->[1]]);
+    } elsif ($c1->[0] == $c2->[0]) {
+      # row
+      push(@return,$arL2C->[$c1->[0]][($c1->[1]+$mode)%5]);
+      push(@return,$arL2C->[$c2->[0]][($c2->[1]+$mode)%5]);
+    } else {
+      # column
+      push(@return,$arL2C->[($c1->[0]+$mode)%5][$c1->[1]]);
+      push(@return,$arL2C->[($c2->[0]+$mode)%5][$c2->[1]]);
+    }
+  } 
+
+  return join('',@return);
+}
+
+