- Added solutions by Arne Sommer.

4 files changed, 92 insertions, 0 deletions

diff --git a/challenge-118/arne-sommer/blog.txt b/challenge-118/arne-sommer/blog.txt
new file mode 100644
index 0000000000..f3efbb4875
--- /dev/null
+++ b/challenge-118/arne-sommer/blog.txt
@@ -0,0 +1 @@
+https://raku-musings.com/binary-knight.html
diff --git a/challenge-118/arne-sommer/perl/ch-1.pl b/challenge-118/arne-sommer/perl/ch-1.pl
new file mode 100644
index 0000000000..1f64526fab
--- /dev/null
+++ b/challenge-118/arne-sommer/perl/ch-1.pl
@@ -0,0 +1,20 @@
+#! /usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+
+use Getopt::Long;
+my $verbose = 0;
+
+GetOptions("verbose" => \$verbose);
+
+my $N = shift(@ARGV);
+
+die "Specify a positive integer" unless $N =~ /^[1-9]\d*$/;
+
+my $bin = sprintf('%b', $N);
+
+say ": $bin (binary)\n: " . reverse($bin) . " (binary flipped)" if $verbose;
+
+say 0 + ($bin eq reverse($bin));
\ No newline at end of file
diff --git a/challenge-118/arne-sommer/raku/ch-1.raku b/challenge-118/arne-sommer/raku/ch-1.raku
new file mode 100644
index 0000000000..1daa749dca
--- /dev/null
+++ b/challenge-118/arne-sommer/raku/ch-1.raku
@@ -0,0 +1,9 @@
+#! /usr/bin/env raku
+
+unit sub MAIN (Int $N where $N > 0, :v($verbose));
+
+my $bin = $N.fmt('%b');
+
+say ": $bin (binary)\n: { $bin.flip } (binary flipped)" if $verbose;
+
+say + ($bin eq $bin.flip);
\ No newline at end of file
diff --git a/challenge-118/arne-sommer/raku/ch-2.raku b/challenge-118/arne-sommer/raku/ch-2.raku
new file mode 100644
index 0000000000..9d8b8fac0d
--- /dev/null
+++ b/challenge-118/arne-sommer/raku/ch-2.raku
@@ -0,0 +1,62 @@
+#! /usr/bin/env raku
+
+subset ChessPos of Str where
+  $_.chars == 2 &&
+  $_.substr(0,1) ~~ /<[abcdefgh]>/ &&
+  $_.substr(1,1) ~~ /<[12345678]>/;
+
+unit sub MAIN (ChessPos $pos = 'a8', :v($verbose));
+  
+my ($col, $row) = $pos.comb;
+
+my %treasures = ('e6' => True, 'c4' => True, 'b3' => True,
+                 'a2' => True, 'b2' => True, 'b1' => True);
+		 
+my %visited   = ('a8' => True);
+
+my @todo = ( ('a8', 'a8', {%visited}, {%treasures}), );
+
+while @todo
+{
+  my $next      = @todo.shift;
+  my ($pos, $path, $visited, $treasures) = @($next);
+  my %visited   = %($visited);
+  my %treasures = %($treasures);
+
+  for get-next($pos) -> $next
+  {
+    say ": Checking pos: $next (at path \'$path\') with { %visited.elems } visits and { %treasures.elems } remaining treasures" if $verbose;
+    next if %visited{$next};
+
+    if %treasures{$next}
+    {
+      if %treasures.elems == 1
+      {
+        say "Path: $path $next";
+        exit;
+      }
+
+      %treasures{$next}:delete;
+    }
+    %visited{$next} = True;
+    @todo.push: ($next, "$path $next", {%visited}, {%treasures});
+  }
+}
+
+sub get-next ($pos)
+{
+  my ($col, $row) = $pos.comb;
+  
+  my @next = (
+    "{ ($col.ord - 2).chr }{ $row - 1 }",  # LLD
+    "{ ($col.ord - 2).chr }{ $row + 1 }",  # LLU
+    "{ ($col.ord - 1).chr }{ $row - 2 }",  # LDD
+    "{ ($col.ord - 1).chr }{ $row + 2 }",  # LUU
+    "{ ($col.ord + 1).chr }{ $row - 2 }",  # RDD
+    "{ ($col.ord + 1).chr }{ $row + 2 }",  # RUU
+    "{ ($col.ord + 2).chr }{ $row - 1 }",  # RRD
+    "{ ($col.ord + 2).chr }{ $row + 1 }",  # RRU
+  ).grep( * ~~ ChessPos);
+
+  return @next;
+}
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