Challenge #53

2 files changed, 86 insertions, 0 deletions

diff --git a/challenge-053/dave-cross/perl/ch-01.pl b/challenge-053/dave-cross/perl/ch-01.pl
new file mode 100644
index 0000000000..c958c67144
--- /dev/null
+++ b/challenge-053/dave-cross/perl/ch-01.pl
@@ -0,0 +1,47 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use feature 'say';
+
+sub print_matrix {
+  my ($matrix) = @_;
+
+  for (@$matrix) {
+    say '[', join(', ', @$_), ']';
+  }
+}
+
+sub rotate_matrix {
+  my ($matrix, $degrees) = @_;
+
+  die "Must give rotation in degrees\n" unless $degrees;
+  die "Must rotate by 90, 180 or 270 degrees\n"
+    if $degrees =~ /\D/ or $degrees % 90 or $degrees > 270;
+
+  my $rotated_matrix;
+
+  for (1 .. $degrees / 90) {
+    $rotated_matrix = [];
+    for my $i (0 .. $#$matrix) {
+      for my $j (0 .. $#{$matrix->[$i]}) {
+        $rotated_matrix->[$j][$#{$matrix->[$i]} - $i] = $matrix->[$i][$j];
+      }
+    }
+    $matrix = $rotated_matrix;
+  }
+
+  return $rotated_matrix;
+}
+
+my $input = [
+  [1, 2 ,3],
+  [4, 5, 6],
+  [7, 8, 9],
+];
+say "Original matrix:";
+print_matrix($input);
+for (90, 180, 270) {
+  say "Rotating by $_ degrees:";
+  print_matrix(rotate_matrix($input, $_));
+}
diff --git a/challenge-053/dave-cross/perl/ch-02.pl b/challenge-053/dave-cross/perl/ch-02.pl
new file mode 100644
index 0000000000..b1ce0a4882
--- /dev/null
+++ b/challenge-053/dave-cross/perl/ch-02.pl
@@ -0,0 +1,39 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use feature 'say';
+
+my $count = get_arg();
+
+my %strings = (
+  a => [qw[e i]],
+  e => [qw[i]],
+  i => [qw[a e o u]],
+  o => [qw[a u]],
+  u => [qw[o e]],
+);
+
+my @words = map { [ $_ ] } keys %strings;
+
+@words = add_letter(@words) for 2 .. $count;
+
+say @$_ for sort { "@$a" cmp "@$b" } @words;
+
+sub get_arg {
+  die "Must give an integer between 1 and 5\n"
+    if !@ARGV or $ARGV[0] =~ /\D/ or ! $ARGV[0] or $ARGV[0] > 5;
+
+  return $ARGV[0];
+}
+
+sub add_letter {
+  my @input = @_;
+  my @output;
+
+  for my $in (@input) {
+    push @output, map { [ @$in, $_ ]} @{$strings{$in->[-1]}};
+  }
+
+  return @output;
+}